[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: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Andy Walls <awalls@md.metrocast.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/pci/ivtv/ivtv-ioctl.c b/drivers/media/pci/ivtv/ivtv-ioctl.c
index 944300f..807b275 100644
--- a/drivers/media/pci/ivtv/ivtv-ioctl.c
+++ b/drivers/media/pci/ivtv/ivtv-ioctl.c
@@ -696,6 +696,8 @@
 {
 	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 &&