MIPS: Audit: Fix hang in entry.S.

_TIF_WORK_MASK false had _TIF_SYSCALL_AUDIT set.  If a thread's
_TIF_SYSCALL_AUDIT is ever set this will lead to an endless loop on the
way out from a syscall.

Currently this is only a theoretic bug as init/Kconfig doesn't allow
AUDIT_SYSCALL to be enabled for MIPS.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/thread_info.h

@@ -146,7 +146,8 @@ register struct thread_info *__current_thread_info __asm__("$28");
 #define _TIF_LOAD_WATCH		(1<<TIF_LOAD_WATCH)
 
 /* work to do on interrupt/exception return */
-#define _TIF_WORK_MASK		(0x0000ffef & ~_TIF_SECCOMP)
+#define _TIF_WORK_MASK		(0x0000ffef &				\
+					~(_TIF_SECCOMP | _TIF_SYSCALL_AUDIT))
 /* work to do on any return to u-space */
 #define _TIF_ALLWORK_MASK	(0x8000ffff & ~_TIF_SECCOMP)