[media] s5p-mfc: Move firmware allocation to DMA configure function

To complete DMA memory configuration for MFC device, allocation of the
firmware buffer is needed, because some parameters are dependant on its base
address. Till now, this has been handled in the s5p_mfc_alloc_firmware()
function. This patch moves that logic to s5p_mfc_configure_dma_memory() to
keep DMA memory related operations in a single place. This way
s5p_mfc_alloc_firmware() is simplified and does what it name says. The
other consequence of this change is moving s5p_mfc_alloc_firmware() call
from the s5p_mfc_probe() function to the s5p_mfc_configure_dma_memory().

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Acked-by: Andrzej Hajda <a.hajda@samsung.com>
Tested-by: Smitha T Murthy <smitha.t@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>