"arm64: Silence gcc warnings about arch ABI drift" breaks clang

[Qian Cai]

The linux-next commit "arm64: Silence gcc warnings about arch ABI drift" [1]
breaks clang build where it screams that unknown option "-Wno-psabi" and
generates errors below,

[1] https://lore.kernel.org/linux-arm-kernel/1559817223-32585-1-git-send-email-D
ave.Martin@xxxxxxx/

./drivers/firmware/efi/libstub/arm-stub.stub.o: In function
`install_memreserve_table':
./linux/drivers/firmware/efi/libstub/arm-stub.c:73: undefined reference to
`__efistub___stack_chk_guard'
./linux/drivers/firmware/efi/libstub/arm-stub.c:73: undefined reference to
`__efistub___stack_chk_guard'
./linux/drivers/firmware/efi/libstub/arm-stub.c:93: undefined reference to
`__efistub___stack_chk_guard'
./linux/drivers/firmware/efi/libstub/arm-stub.c:93: undefined reference to
`__efistub___stack_chk_guard'
./linux/drivers/firmware/efi/libstub/arm-stub.c:94: undefined reference to
`__efistub___stack_chk_fail