vt: NULL dereference in vt_do_kdsk_ioctl()

We forgot to set the "key_map" variable here, so it's still NULL.  This
was introduced recently in 079c9534 "vt:tackle kbd_table".
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/vt/keyboard.c

@@ -1863,6 +1863,7 @@ int vt_do_kdsk_ioctl(int cmd, struct kbentry __user *user_kbe, int perm,
 				return -EPERM;
 			}
 			key_maps[s] = new_map;
+			key_map = new_map;
 			key_map[0] = U(K_ALLOCATED);
 			for (j = 1; j < NR_KEYS; j++)
 				key_map[j] = U(K_HOLE);