media: fc2580: fix tuning failure on 32-bit arch

commit 8845cc6415ec28ef8d57b3fb81c75ef9bce69c5f upstream.

There was some frequency calculation overflows which caused tuning
failure on 32-bit architecture. Use 64-bit numbers where needed in
order to avoid calculation overflows.

Thanks for the Finnish person, who asked remain anonymous, reporting,
testing and suggesting the fix.

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>