[media] radio-tea5777.c: Get rid of do_div usage

freq fits easily into 32 bits until it gets shifted, so make it 32 bits,
and cast it to 64 bits before shifting.

[mchehab@redhat.com: also remove asm/div64.h header, as this is not
 needed anymore]
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>