staging/bcm2835-codec: bytesperline for YUV420/YVU420 needs to be 64

Matching https://github.com/raspberrypi/linux/pull/4419

, the ISP
block (which is also used on the input of the encoder, and output
of the decoder) needs the base address of all planes to be aligned
to multiples of 32. This includes the chroma planes of YUV420 and
YVU420.
If the height is only a multiple of 2 (not 4), then you get an odd
number of lines in the second plane, which means the 3rd plane
starts at a multiple of bytesperline/2.

Set the minimum bytesperline alignment to 64 for those formats
so that the plane alignment is always right.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>