V4L/DVB (9472): dm1105: fix the misuse of pci_dma_mapping_error

pci_dma_mapping_error can't be used for pci_alloc_consistent
(pci_dma_mapping_error is for dma_map_single and dma_map_page).
pci_alloc_consistent returns NULL if the allocation fails.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Igor M. Liplianin <liplianin@me.by>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>