[dev][timer][arm_generic] Add arm64 support and select timer based on TIMER_ARM_GENERIC_SELECTED
[dev][timer][arm_generic] Add arm64 support and select timer based on TIMER_ARM_GENERIC_SELECTED

TIMER_ARM_GENERIC_SELECTED can be set to CNTP, CNTPS or CNTV. CNTP is
used by default.

Change-Id: Idbce233062f244cee8245f48c6ad272111b7c58b

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