sh: Fix sys_pwritev() syscall table entry for sh32.

There was a typo here that had this as sys_writev() instead of
sys_pwritev(), fix this up. sh64 got this right, as did the preadv()
case.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

arch/sh/kernel/syscalls_32.S

@@ -350,4 +350,4 @@ ENTRY(sys_call_table)
 	.long sys_pipe2
 	.long sys_inotify_init1
 	.long sys_preadv
-	.long sys_writev
+	.long sys_pwritev