media: dvb-frontends: tda18271c2dd: Remove casting during div

do_div() divides 64 bits by 32. We were adding a casting to the divider
to 64 bits, for a number that fits perfectly in 32 bits. Remove it.

Found by cocci:
drivers/media/dvb-frontends/tda18271c2dd.c:355:1-7: WARNING: do_div() does a 64-by-32 division, please consider using div64_u64 instead.
drivers/media/dvb-frontends/tda18271c2dd.c:331:1-7: WARNING: do_div() does a 64-by-32 division, please consider using div64_u64 instead.

Link: https://lore.kernel.org/linux-media/20240429-fix-cocci-v3-8-3c4865f5a4b0@chromium.org
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>