Use pointer authentication for kernel

CONFIG_ARM64_PTR_AUTH_KERNEL is not available for the default architecture x86.
Result is shown for architecture arm64

depends

CONFIG_ARM64_PTR_AUTH
CONFIG_AS_HAS_PAC
CONFIG_CC_HAS_BRANCH_PROT_PAC_RET or CONFIG_CC_HAS_SIGN_RETURN_ADDRESS
CONFIG_AS_HAS_CFI_NEGATE_RA_STATE or NOT CONFIG_CC_IS_CLANG
CONFIG_DYNAMIC_FTRACE_WITH_ARGS or NOT CONFIG_FUNCTION_GRAPH_TRACER
CONFIG_LD_IS_LLD or CONFIG_LD_VERSION=CONFIG_23301 or CONFIG_CC_IS_GCC
CONFIG_GCC_VERSION=CONFIG_90100

is selected by

CONFIG_UNWIND_PATCH_PAC_INTO_SCS

configname: CONFIG_ARM64_PTR_AUTH_KERNEL

Linux Kernel Configuration

└─> Kernel Features

└─> ARMv8.3 architectural features

└─> Use pointer authentication for kernel

If the compiler supports the -mbranch-protection or
-msign-return-address flag (e.g. GCC 7 or later), then this option
will cause the kernel itself to be compiled with return address
protection. In this case, and if the target hardware is known to
support pointer authentication, then CONFIG_STACKPROTECTOR can be
disabled with minimal loss of protection.

This feature works with FUNCTION_GRAPH_TRACER option only if
DYNAMIC_FTRACE_WITH_ARGS is enabled.