[arch][arm/arm64] Define make variables to enable use of optional simd instructions.

Support for these instructions can be detected at runtime, but then the unused
code cannot be eliminated at build time.

Change-Id: I51fae84fe4dfb5c9741d732f1f04ac765339175a

arch/arm/rules.mk

@@ -208,6 +208,13 @@ ifneq ($(ARM_WITHOUT_VFP_NEON),true)
 GLOBAL_DEFINES += \
 	ARM_WITH_VFP=1 \
 	ARM_WITH_NEON=1
+
+# Enable optional instructions unless platform already disabled them
+USE_ARM_V7_NEON ?= true
+USE_ARM_V8_AES ?= true
+USE_ARM_V8_PMULL ?= true
+USE_ARM_V8_SHA1 ?= true
+USE_ARM_V8_SHA2 ?= true
 endif
 HANDLED_CORE := true
 endif

arch/arm64/rules.mk

@@ -46,6 +46,15 @@ GLOBAL_DEFINES += \
     SMP_MAX_CPUS=1
 endif
 
+ifeq (false,$(call TOBOOL,$(ARM_WITHOUT_VFP_NEON)))
+# Enable optional instructions unless platform already disabled them
+USE_ARM_V7_NEON ?= true
+USE_ARM_V8_AES ?= true
+USE_ARM_V8_PMULL ?= true
+USE_ARM_V8_SHA1 ?= true
+USE_ARM_V8_SHA2 ?= true
+endif
+
 ARCH_OPTFLAGS := -O2
 
 # we have a mmu and want the vmm/pmm