[media] V4L2: mx3_camera: print V4L2_MBUS_FMT_* codes in hexadecimal format

V4L2_MBUS_FMT_* codes are defined in v4l2-mediabus.h as hexadecimal
constants. Print them in the same form for easier recognition.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>