[media] cx25840: Fix compilation for i386 architecture

WARNING: "__udivdi3" [/home/v4l/new_build/v4l/cx25840.ko] undefined!

64 bits division need to call do_div & friends, in order to allow
it to compile with 32 bits kernels

Cc: Steven Toth <stoth@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>