media: siano: use GFP_DMA only for smssdio

Right now, the Siano's core uses GFP_DMA for both USB and
SDIO variants of the driver. There's no reason to use it
for USB. So, pass GFP_DMA as a parameter during sms core
register.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>