media: dib9000: Use min() instead of doing it manually

Fix following coccicheck warning:
drivers/media/dvb-frontends/dib9000.c:261:10-11: WARNING opportunity for min()
drivers/media/dvb-frontends/dib9000.c:345:10-11: WARNING opportunity for min()

Link: https://lore.kernel.org/linux-media/20211117030656.14984-1-zhaoxiao@uniontech.com



Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, zhaoxiao <zhaoxiao@uniontech.com>
Signed-off-by: zhaoxiao <zhaoxiao@uniontech.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>