media: st-hva: don't use GFP_DMA

Set the DMA_MASK and stop using the GFP_DMA flag

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Hans Verkuil <hansverk@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>