ArmPkg/ArmMmuLib: AARCH64: enable stack alignment checking

Enable the hardware stack alignment check, as mandated by the UEFI spec.
This ensures that the stack pointer is 16 byte aligned at each instance
where it is used as the base address in a load/store operation.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>

ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c

@@ -734,6 +734,7 @@ ArmConfigureMmu (
               MAIR_ATTR(TT_ATTR_INDX_MEMORY_WRITE_BACK, MAIR_ATTR_NORMAL_MEMORY_WRITE_BACK));       // mapped to EFI_MEMORY_WB
 
   ArmDisableAlignmentCheck ();
+  ArmEnableStackAlignmentCheck ();
   ArmEnableInstructionCache ();
   ArmEnableDataCache ();