parisc: Drop TIF_RESTORE_SIGMASK and switch to generic code

Commit 7e781418 ("signal: consolidate {TS,TLF}_RESTORE_SIGMASK code")
introduced code with which the "restore sigmask" flag lives in task_struct
instead of ti->flags. Let's use this optimization on parisc too.
Signed-off-by: Helge Deller <deller@gmx.de>

arch/parisc/include/asm/thread_info.h

@@ -49,7 +49,6 @@ struct thread_info {
 #define TIF_POLLING_NRFLAG	3	/* true if poll_idle() is polling TIF_NEED_RESCHED */
 #define TIF_32BIT               4       /* 32 bit binary */
 #define TIF_MEMDIE		5	/* is terminating due to OOM killer */
-#define TIF_RESTORE_SIGMASK	6	/* restore saved signal mask */
 #define TIF_SYSCALL_AUDIT	7	/* syscall auditing active */
 #define TIF_NOTIFY_RESUME	8	/* callback before returning to user */
 #define TIF_SINGLESTEP		9	/* single stepping? */