arm64: Kconfig: verify binutils support for ARM64_PTR_AUTH

Clang relies on GNU as from binutils to assemble the Linux kernel,
currently. A recent patch to enable the armv8.3-a extension for pointer
authentication checked for compiler support of the relevant flags.
Everything works with binutils 2.34+, but for older versions we observe
assembler errors:

/tmp/vgettimeofday-36a54b.s: Assembler messages:
/tmp/vgettimeofday-36a54b.s:40: Error: unknown pseudo-op: `.cfi_negate_ra_state'

When compiling with Clang, require the assembler to support
.cfi_negate_ra_state directives, in order to support CONFIG_ARM64_PTR_AUTH.

Link: https://github.com/ClangBuiltLinux/linux/issues/938


Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>