[media] lm3560: prevent memory leak in case of pdata absence

If we have no pdata defined and driver fails to register we leak memory.
Converting to devm_kzalloc prevents this to happen.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>