ARM64: trivial: s/TIF_SECOMP/TIF_SECCOMP/ comment typo fix

Fix a s/TIF_SECOMP/TIF_SECCOMP/ comment typo

Cc: Jiri Kosina <trivial@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: George G. Davis <george_davis@mentor.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>