V4L/DVB: radio-si470x: Use UTF-8 encoding on a comment

This cosmetic patch corrects a wrong unicode "micro" character in a comment.
Signed-off-by: NTobias Lorenz <tobias.lorenz@gmx.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/radio/si470x/radio-si470x-common.c

@@ -724,7 +724,7 @@ static int si470x_vidioc_g_tuner(struct file *file, void *priv,
 		tuner->audmode = V4L2_TUNER_MODE_MONO;
 
 	/* min is worst, max is best; signal:0..0xffff; rssi: 0..0xff */
-	/* measured in units of db쨉V in 1 db increments (max at ~75 db쨉V) */
+	/* measured in units of dbµV in 1 db increments (max at ~75 dbµV) */
 	tuner->signal = (radio->registers[STATUSRSSI] & STATUSRSSI_RSSI);
 	/* the ideal factor is 0xffff/75 = 873,8 */
 	tuner->signal = (tuner->signal * 873) + (8 * tuner->signal / 10);