feat(fvp_r): configure system registers to boot rich OS

Following system registers are modified before exiting EL2 to allow
u-boot/Linux to boot
     Allows U-boot to use physical counters at EL1
  2. VTCR_EL2.MSA -> 1
     Enables VMSA at EL1, which is required by U-Boot and Linux.
  3. HCR_EL2.APK = 1 & HCR_EL2.API = 1
     Disables PAuth instruction and register traps in EL1

Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Change-Id: I58f45b6669a9ad1debb80265b243015c054a9bb1
4 files changed