media: av7110_v4l: avoid a typecast

While smatch reports an issue there:

	drivers/media/pci/ttpci/av7110_v4l.c:163 ves1820_set_tv_freq() warn: unsigned 'freq' is never less than zero.
	drivers/media/pci/ttpci/av7110_v4l.c:165 ves1820_set_tv_freq() warn: unsigned 'freq' is never less than zero.

The logic is actually fine. Yet, removing the typecast
shuts up smatch and makes the code more readable.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/pci/ttpci/av7110_v4l.c

@@ -160,9 +160,9 @@ static int ves1820_set_tv_freq(struct saa7146_dev *dev, u32 freq)
 	buf[1] = div & 0xff;
 	buf[2] = 0x8e;
 
-	if (freq < (u32) (16 * 168.25))
+	if (freq < 16U * 168.25)
 		config = 0xa0;
-	else if (freq < (u32) (16 * 447.25))
+	else if (freq < 16U * 447.25)
 		config = 0x90;
 	else
 		config = 0x30;