x86: change k_rtsigset_t sig type

As it has equall size for compat/native tasks.
Fixes for compatible tasks:
pie: Daemon waits for command
(00.009247) Fetched ack: 7 7 0
pie: __fetched msg: 9 0 0
pie: Error (pie/parasite.c:106): sys_sigaction failed (-22)
pie: __sent ack msg: 9 9 -22
pie: Error (pie/parasite.c:725): Close the control socket for writing

Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/arch/x86/include/asm/types.h

@@ -38,7 +38,7 @@ typedef rt_restorefn_t *rt_sigrestore_t;
 #define _KNSIG_WORDS     (_KNSIG / _NSIG_BPW)
 
 typedef struct {
-	unsigned long sig[_KNSIG_WORDS];
+	u64 sig[_KNSIG_WORDS];
 } k_rtsigset_t;
 
 #define SA_RESTORER	0x04000000