staging: rtl8192u: r8192U_wx: fix negative noise and level values

range->max_qual.noise and level are of type uint8, so they shouldn't be
assigned a negative number. Assigning them 0x100 - 98, and 0x100 - 78 which
are the equivalent to -98 dBm and -78 dBm, respectively, when IW_QUAL_DBM
is set.
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192u/r8192U_wx.c

@@ -263,12 +263,12 @@ static int rtl8180_wx_get_range(struct net_device *dev,
 	range->max_qual.qual = 100;
 	/* TODO: Find real max RSSI and stick here */
 	range->max_qual.level = 0;
-	range->max_qual.noise = -98;
+	range->max_qual.noise = 0x100 - 98;
 	range->max_qual.updated = 7; /* Updated all three */
 
 	range->avg_qual.qual = 92; /* > 8% missed beacons is 'bad' */
 	/* TODO: Find real 'good' to 'bad' threshold value for RSSI */
-	range->avg_qual.level = 20 + -98;
+	range->avg_qual.level = 0x100 - 78;
 	range->avg_qual.noise = 0;
 	range->avg_qual.updated = 7; /* Updated all three */