Fixes these warnings:

drivers/media/pci/cobalt/cobalt-omnitek.c: In function 'omni_sg_dma_start':
drivers/media/pci/cobalt/cobalt-omnitek.c:112:28: warning: right shift count >= width of type [-Wshift-count-overflow]
  iowrite32((u32)(desc->bus >> 32), DESCRIPTOR(s->dma_channel) + 4);
                            ^
drivers/media/pci/cobalt/cobalt-omnitek.c: In function 'descriptor_list_create':
drivers/media/pci/cobalt/cobalt-omnitek.c:222:28: warning: right shift count >= width of type [-Wshift-count-overflow]
     d->next_h = (u32)(next >> 32);
                            ^
drivers/media/pci/cobalt/cobalt-omnitek.c:268:32: warning: right shift count >= width of type [-Wshift-count-overflow]
    d->next_h = (u32)(desc->bus >> 32);
                                ^
drivers/media/pci/cobalt/cobalt-omnitek.c:275:27: warning: right shift count >= width of type [-Wshift-count-overflow]
    d->next_h = (u32)(next >> 32);
                           ^
drivers/media/pci/cobalt/cobalt-omnitek.c: In function 'descriptor_list_chain':
drivers/media/pci/cobalt/cobalt-omnitek.c:293:31: warning: right shift count >= width of type [-Wshift-count-overflow]
   d->next_h = (u32)(next->bus >> 32);
                               ^
drivers/media/pci/cobalt/cobalt-omnitek.c: In function 'descriptor_list_loopback':
drivers/media/pci/cobalt/cobalt-omnitek.c:332:30: warning: right shift count >= width of type [-Wshift-count-overflow]
  d->next_h = (u32)(desc->bus >> 32);
                              ^
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>