arch: add pkey and rseq syscall numbers everywhere

Most architectures define system call numbers for the rseq and pkey system
calls, even when they don't support the features, and perhaps never will.

Only a few architectures are missing these, so just define them anyway
for consistency. If we decide to add them later to one of these, the
system call numbers won't get out of sync then.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>

arch/xtensa/kernel/syscalls/syscall.tbl

@@ -372,3 +372,4 @@
 349	common	pkey_alloc			sys_pkey_alloc
 350	common	pkey_free			sys_pkey_free
 351	common	statx				sys_statx
+352	common	rseq				sys_rseq