V4L/DVB (7739): mt312.h: dubious one-bit signed bitfield

Make it unsigned (0/1) rather than signed (0/-1).
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/dvb/frontends/mt312.h

@@ -33,7 +33,7 @@ struct mt312_config {
 	u8 demod_address;
 
 	/* inverted voltage setting */
-	int voltage_inverted:1;
+	unsigned int voltage_inverted:1;
 };
 
 #if defined(CONFIG_DVB_MT312) || (defined(CONFIG_DVB_MT312_MODULE) && defined(MODULE))