media: marvell-ccic: mmp: don't chicken out w/o pdata

It's impossible for mmpcam_calc_dphy() to be called without it.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>