[media] solo6x10: fix sparse warnings

drivers/media/pci/solo6x10/solo6x10-disp.c:184:24: warning: incorrect type in assignment (different base types)
drivers/media/pci/solo6x10/solo6x10-disp.c:223:32: warning: incorrect type in assignment (different base types)

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>