MIPS: Document former use of timerfd(2) syscall number.

Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/kernel/scall32-o32.S

@@ -565,7 +565,7 @@ einval:	li	v0, -ENOSYS
 	sys	sys_ioprio_get		2	/* 4315 */
 	sys	sys_utimensat		4
 	sys	sys_signalfd		3
-	sys	sys_ni_syscall		0
+	sys	sys_ni_syscall		0	/* was timerfd */
 	sys	sys_eventfd		1
 	sys	sys_fallocate		6	/* 4320 */
 	sys	sys_timerfd_create	2

arch/mips/kernel/scall64-64.S

@@ -404,7 +404,7 @@ sys_call_table:
 	PTR	sys_ioprio_get
 	PTR	sys_utimensat			/* 5275 */
 	PTR	sys_signalfd
-	PTR	sys_ni_syscall
+	PTR	sys_ni_syscall			/* was timerfd */
 	PTR	sys_eventfd
 	PTR	sys_fallocate
 	PTR	sys_timerfd_create		/* 5280 */

arch/mips/kernel/scall64-n32.S

@@ -403,7 +403,7 @@ EXPORT(sysn32_call_table)
 	PTR	sys_ioprio_get
 	PTR	compat_sys_utimensat
 	PTR	compat_sys_signalfd		/* 6280 */
-	PTR	sys_ni_syscall
+	PTR	sys_ni_syscall			/* was timerfd */
 	PTR	sys_eventfd
 	PTR	sys_fallocate
 	PTR	sys_timerfd_create

arch/mips/kernel/scall64-o32.S

@@ -522,7 +522,7 @@ sys_call_table:
 	PTR	sys_ioprio_get			/* 4315 */
 	PTR	compat_sys_utimensat
 	PTR	compat_sys_signalfd
-	PTR	sys_ni_syscall
+	PTR	sys_ni_syscall			/* was timerfd */
 	PTR	sys_eventfd
 	PTR	sys32_fallocate			/* 4320 */
 	PTR	sys_timerfd_create