[media] ivtv: 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: NHans Verkuil <hans.verkuil@cisco.com>
Cc: Andy Walls <awalls@md.metrocast.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

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

@@ -696,6 +696,8 @@ static int ivtv_itvc(struct ivtv *itv, bool get, u64 reg, u64 *val)
 {
 	volatile u8 __iomem *reg_start;
 
+	if (reg & 0x3)
+		return -EINVAL;
 	if (reg >= IVTV_REG_OFFSET && reg < IVTV_REG_OFFSET + IVTV_REG_SIZE)
 		reg_start = itv->reg_mem - IVTV_REG_OFFSET;
 	else if (itv->has_cx23415 && reg >= IVTV_DECODER_OFFSET &&