ANDROID: Disable BTI_KERNEL, enable UNWIND_PATCH_PAC_INTO_SCS

Disable CONFIG_ARM64_BTI_KERNEL since significant overhead has been observed
on systems that don't have BTI/PAC hardware support due to increased number
of NOPs added by these features.

BTI is not as important in kernels that have CFI enabled because the protection
these features offer overlap.

Keep PAC enabled and also enable dynamic SCS (CONFIG_UNWIND_PATCH_PAC_INTO_SCS)
which is available starting in v6.2. This removes SCS overhead on systems that
support PAC, and PAC overhead on systems that need SCS instead. This feature uses
runtime code patching, so it won't have the overhead of additional NOPs.

Bug: 267119345
Change-Id: Ifc7d5e502940bd15d13e7f89c5facd10b6c7b8a8
Signed-off-by: Todd Kjos <tkjos@google.com>