flash.ld: fix mis-aligned .data section
flash.ld: fix mis-aligned .data section

The end of the .data section in flash must be explicitly word-aligned,
otherwise corruption can occur in a .data section that happens to contain
non-word aligned data.

sandeepmistry/corelibs-arduino101,bigdinotech/corelibs-arduino101,sgbihu/corelibs-arduino101,bigdinotech/corelibs-arduino101,SidLeung/corelibs-arduino101,yashaswini-hanji/corelibs-arduino101,01org/corelibs-arduino101,sgbihu/corelibs-arduino101,yashaswini-hanji/corelibs-arduino101,yashaswini-hanji/corelibs-arduino101,01org/corelibs-arduino101,SidLeung/corelibs-arduino101,bigdinotech/corelibs-arduino101,sgbihu/corelibs-arduino101,sandeepmistry/corelibs-arduino101,sandeepmistry/corelibs-arduino101,01org/corelibs-arduino101