ArmPlatformPkg/NorFlashDxe: depend on gEfiCpuArchProtocolGuid

ArmPlatformPkg/NorFlashDxe: depend on gEfiCpuArchProtocolGuid

NorFlashFvbInitialize() calls gDS->SetMemorySpaceAttributes() to mark the
varstore flash region as uncached. This DXE service depends on the CPU
Architectural protocol, and the DXE core is allowed to return
EFI_NOT_AVAILABLE_YET if it hasn't dispatched ArmPkg/Drivers/CpuDxe
earlier. Make the dependency explicit.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Supreeth Venkatesh <Supreeth.Venkatesh@arm.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Steve Capper <steve.capper@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>