unittests/tests-spiffs: fix dummy memory layout
unittests/tests-spiffs: fix dummy memory layout

Use 8 pages per sector to comply with spiffs requirements:
 - page_size must be block_size / (2^y) where y > 2

gautric/RIOT,adjih/RIOT,authmillenon/RIOT,neumodisch/RIOT,immesys/RiSyn,josephnoir/RIOT,smlng/RIOT,x3ro/RIOT,kerneltask/RIOT,aeneby/RIOT,miri64/RIOT,roberthartung/RIOT,hamilton-mote/RIOT-OS,immesys/RiSyn,yogo1212/RIOT,cladmi/RIOT,beurdouche/RIOT,kbumsik/RIOT,jfischer-phytec-iot/RIOT,avmelnikoff/RIOT,authmillenon/RIOT,A-Paul/RIOT,basilfx/RIOT,x3ro/RIOT,LudwigKnuepfer/RIOT,adjih/RIOT,x3ro/RIOT,kYc0o/RIOT,Josar/RIOT,lazytech-org/RIOT,yogo1212/RIOT,dailab/RIOT,gautric/RIOT,ks156/RIOT,smlng/RIOT,toonst/RIOT,adrianghc/RIOT,dkm/RIOT,lazytech-org/RIOT,ks156/RIOT,OTAkeys/RIOT,BytesGalore/RIOT,hamilton-mote/RIOT-OS,toonst/RIOT,x3ro/RIOT,ks156/RIOT,rfuentess/RIOT,LudwigOrtmann/RIOT,RIOT-OS/RIOT,ant9000/RIOT,aeneby/RIOT,mtausig/RIOT,thomaseichinger/RIOT,yogo1212/RIOT,Ell-i/RIOT,ant9000/RIOT,adrianghc/RIOT,immesys/RiSyn,miri64/RIOT,OlegHahm/RIOT,kbumsik/RIOT,Hyungsin/RIOT-OS,BytesGalore/RIOT,mtausig/RIOT,neumodisch/RIOT,gautric/RIOT,kYc0o/RIOT,rfuentess/RIOT,gebart/RIOT,Ell-i/RIOT,kbumsik/RIOT,adrianghc/RIOT,toonst/RIOT,gebart/RIOT,rfuentess/RIOT,ks156/RIOT,thomaseichinger/RIOT,syin2/RIOT,OTAkeys/RIOT,Josar/RIOT,beurdouche/RIOT,roberthartung/RIOT,avmelnikoff/RIOT,plushvoxel/RIOT,kaleb-himes/RIOT,biboc/RIOT,authmillenon/RIOT,authmillenon/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,LudwigOrtmann/RIOT,A-Paul/RIOT,gebart/RIOT,Ell-i/RIOT,dkm/RIOT,A-Paul/RIOT,jfischer-phytec-iot/RIOT,gebart/RIOT,neiljay/RIOT,jfischer-phytec-iot/RIOT,authmillenon/RIOT,biboc/RIOT,neiljay/RIOT,kaleb-himes/RIOT,neiljay/RIOT,dkm/RIOT,neumodisch/RIOT,dailab/RIOT,A-Paul/RIOT,lazytech-org/RIOT,beurdouche/RIOT,rfuentess/RIOT,kaleb-himes/RIOT,syin2/RIOT,aeneby/RIOT,yogo1212/RIOT,neiljay/RIOT,RIOT-OS/RIOT,kaspar030/RIOT,biboc/RIOT,kaspar030/RIOT,mfrey/RIOT,syin2/RIOT,LudwigKnuepfer/RIOT,adjih/RIOT,adrianghc/RIOT,gautric/RIOT,kerneltask/RIOT,plushvoxel/RIOT,OlegHahm/RIOT,jasonatran/RIOT,beurdouche/RIOT,aeneby/RIOT,kerneltask/RIOT,BytesGalore/RIOT,miri64/RIOT,kaleb-himes/RIOT,kYc0o/RIOT,dailab/RIOT,biboc/RIOT,ant9000/RIOT,immesys/RiSyn,miri64/RIOT,thomaseichinger/RIOT,cladmi/RIOT,LudwigOrtmann/RIOT,ks156/RIOT,Ell-i/RIOT,kerneltask/RIOT,mfrey/RIOT,smlng/RIOT,Josar/RIOT,adjih/RIOT,kbumsik/RIOT,mtausig/RIOT,plushvoxel/RIOT,roberthartung/RIOT,RIOT-OS/RIOT,OTAkeys/RIOT,dailab/RIOT,LudwigOrtmann/RIOT,hamilton-mote/RIOT-OS,OTAkeys/RIOT,RIOT-OS/RIOT,immesys/RiSyn,dkm/RIOT,OlegHahm/RIOT,dailab/RIOT,Ell-i/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,OTAkeys/RIOT,roberthartung/RIOT,kbumsik/RIOT,avmelnikoff/RIOT,plushvoxel/RIOT,hamilton-mote/RIOT-OS,josephnoir/RIOT,jfischer-phytec-iot/RIOT,cladmi/RIOT,BytesGalore/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,LudwigKnuepfer/RIOT,neumodisch/RIOT,LudwigKnuepfer/RIOT,LudwigKnuepfer/RIOT,lazytech-org/RIOT,jasonatran/RIOT,toonst/RIOT,basilfx/RIOT,neumodisch/RIOT,josephnoir/RIOT,OlegHahm/RIOT,cladmi/RIOT,Hyungsin/RIOT-OS,rfuentess/RIOT,Hyungsin/RIOT-OS,smlng/RIOT,syin2/RIOT,cladmi/RIOT,authmillenon/RIOT,avmelnikoff/RIOT,jasonatran/RIOT,kYc0o/RIOT,mtausig/RIOT,thomaseichinger/RIOT,kaspar030/RIOT,kYc0o/RIOT,Josar/RIOT,kaleb-himes/RIOT,josephnoir/RIOT,jfischer-phytec-iot/RIOT,avmelnikoff/RIOT,roberthartung/RIOT,hamilton-mote/RIOT-OS,basilfx/RIOT,mfrey/RIOT,thomaseichinger/RIOT,mtausig/RIOT,miri64/RIOT,basilfx/RIOT,biboc/RIOT,kaspar030/RIOT,josephnoir/RIOT,ant9000/RIOT,RIOT-OS/RIOT,LudwigOrtmann/RIOT,neumodisch/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,BytesGalore/RIOT,yogo1212/RIOT,syin2/RIOT,dkm/RIOT,adrianghc/RIOT,lazytech-org/RIOT,plushvoxel/RIOT,beurdouche/RIOT,neiljay/RIOT,ant9000/RIOT,gautric/RIOT,LudwigOrtmann/RIOT,Josar/RIOT,kerneltask/RIOT,basilfx/RIOT,OlegHahm/RIOT,jasonatran/RIOT,toonst/RIOT,kaspar030/RIOT,aeneby/RIOT,mfrey/RIOT,adjih/RIOT,Hyungsin/RIOT-OS,mfrey/RIOT,immesys/RiSyn,gebart/RIOT,jasonatran/RIOT,Hyungsin/RIOT-OS,x3ro/RIOT,yogo1212/RIOT,A-Paul/RIOT,smlng/RIOT