FROMGIT: arm64: Introduce esr_brk_comment, esr_is_cfi_brk

As it is already used in two places, move esr_comment() to a header for
re-use, with a clearer name.

Introduce esr_is_cfi_brk() to detect kCFI BRK syndromes, currently used
by early_brk64() but soon to also be used by hypervisor code.

Bug: 278010198
Bug: 278749606
(cherry picked from commit 7a928b32
 https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git

 )
Change-Id: I233a9bf5aef94d97755a6c9b5254c36127e07355
Signed-off-by: Pierre-Clément Tosi <ptosi@google.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20240610063244.2828978-7-ptosi@google.com


Signed-off-by: Oliver Upton <oliver.upton@linux.dev>