vc04_services: bcm2835-codec: Correct alignment requirements for YUYV

The firmware wants the YUYV format stride alignment to be to a multiple
of 32pixels / 64 bytes. The kernel driver was configuring it to a multiple
of 16 pixels / 32 bytes, which then failed when it tried starting to
stream.

Correct the alignment requirements.

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