edk2-firmware: Do release builds even on clang

Release builds with clang were fixed in 202202. We can drop this
workaround now as we are on that version.

Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>
Signed-off-by: Luca Seritan <luca.seritan@huawei.com>

meta-oniro-staging/recipes-bsp/uefi/edk2-firmware_%.bbappend

@@ -5,6 +5,8 @@
 export GCC5_ARM_PREFIX = "${TARGET_PREFIX}"
 export CLANG38_ARM_PREFIX = "${TARGET_PREFIX}"
 
+EDK2_BUILD_RELEASE:toolchain-clang = "1"
+
 do_install:prepend() {
 	# Some platforms use an ARCH suffix.
 	if [ ! -e "${B}/Build/${EDK2_PLATFORM}" ]; then