[media] cx18: fix register range check

Ensure that the register is aligned to a dword, otherwise the range check
could fail since it assumes dword alignment.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Andy Walls <awalls@md.metrocast.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/pci/cx18/cx18-ioctl.c

@@ -367,6 +367,8 @@ static int cx18_g_register(struct file *file, void *fh,
 {
 	struct cx18 *cx = fh2id(fh)->cx;
 
+	if (reg->reg & 0x3)
+		return -EINVAL;
 	if (reg->reg >= CX18_MEM_OFFSET + CX18_MEM_SIZE)
 		return -EINVAL;
 	reg->size = 4;
@@ -379,6 +381,8 @@ static int cx18_s_register(struct file *file, void *fh,
 {
 	struct cx18 *cx = fh2id(fh)->cx;
 
+	if (reg->reg & 0x3)
+		return -EINVAL;
 	if (reg->reg >= CX18_MEM_OFFSET + CX18_MEM_SIZE)
 		return -EINVAL;
 	cx18_write_enc(cx, reg->val, reg->reg);