staging: vc04_services: isp: Set the YUV420/YVU420 format stride to 64 bytes

The bcm2835 ISP requires the base address of all input/output planes to have 32
byte alignment. Using a Y stride of 32 bytes would not guarantee that the V
plane would fulfil this, e.g. a height of 650 lines would mean the V plane
buffer is not 32 byte aligned for YUV420 formats.

Having a Y stride of 64 bytes would ensure both U and V planes have a 32 byte
alignment, as the luma height will always be an even number of lines.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>