[arch][arm] Add memory barriers.
[arch][arm] Add memory barriers.

sndnvaps/lk,minglun-tsai/lk,skabet/lk,minglun-tsai/lk,GCrean/lk,skabet/lk,minglun-tsai/lk,nvll/lk,grub4android/lk,pablomarx/lk,grub4android/lk,nvll/lk,M1cha/lk,M1cha/lk,M1cha/lk,ianloic/lk,M1cha/lk,sndnvaps/lk,sndnvaps/lk,skabet/lk,nvll/lk,travisg/lk,travisg/lk,littlekernel/lk,grub4android/lk,srodrig1/lk,GCrean/lk,ianloic/lk,hollanderic/lkstuff,ErikCorryGoogle/lk,littlekernel/lk,nvll/lk,M1cha/lk,GCrean/lk,pablomarx/lk,littlekernel/lk,ErikCorryGoogle/lk,pablomarx/lk,pablomarx/lk,ianloic/lk,srodrig1/lk,hollanderic/lkstuff,travisg/lk,GCrean/lk,skabet/lk,pablomarx/lk,srodrig1/lk,ErikCorryGoogle/lk,grub4android/lk,sndnvaps/lk,srodrig1/lk,sndnvaps/lk,grub4android/lk,hollanderic/lkstuff,hollanderic/lkstuff,nvll/lk,minglun-tsai/lk,travisg/lk,skabet/lk,ErikCorryGoogle/lk,srodrig1/lk,GCrean/lk,littlekernel/lk,ianloic/lk