drivers/hid/uhid.c: check write() bitness using in_compat_syscall

uhid changes the format expected in write() depending on bitness.  It
should check the syscall bitness directly.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: David Herrmann <dh.herrmann@googlemail.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/hid/uhid.c

@@ -384,7 +384,7 @@ struct uhid_create_req_compat {
 static int uhid_event_from_user(const char __user *buffer, size_t len,
 				struct uhid_event *event)
 {
-	if (is_compat_task()) {
+	if (in_compat_syscall()) {
 		u32 type;
 
 		if (get_user(type, buffer))