refactor(qemu): keep AArch64 cpu flags in one section

There is no need to have two "if" checks for same thing one after
another.

FGT, RNG, SVE, SME are aarch64 only flags.

Change-Id: I6e5850211c859dc7a4ccf6bc8dc6a8d600ffe692
Signed-off-by: Marcin Juszkiewicz <marcin.juszkiewicz@linaro.org>

plat/qemu/common/common.mk

@@ -85,7 +85,6 @@ else
 	ENABLE_SVE_FOR_NS	:= 2
 	ENABLE_SME_FOR_NS	:= 2
 endif
-endif
 
 # QEMU will use the RNDR instruction for the stack protector canary.
 ENABLE_FEAT_RNG			:= 2
@@ -93,7 +92,6 @@ ENABLE_FEAT_RNG			:= 2
 # QEMU 7.2+ has support for FGT and Linux needs it enabled to boot on max
 ENABLE_FEAT_FGT			:= 2
 
-ifeq (${ARCH},aarch64)
 # Treating this as a memory-constrained port for now
 USE_COHERENT_MEM	:=	0