x86/syscalls: Don't adjust CFLAGS for syscall tables

The syscall_*.c files only contain data (the syscall tables).  There
is no need to adjust CFLAGS for tracing and stack protector since they
contain no code.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20210524181707.132844-4-brgerst@gmail.com