[media] ARM: mach-shmobile: convert mackerel to mediabus flags

Prepare the board to switch to the new subdevice media-bus configuration
operations.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>