media: common: saa7146: fix broken V4L2_PIX_FMT_YUV422P support

The U and V components were swapped. Drop the FORMAT_BYTE_SWAP
to fix this.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>