wpa_supplicant: Fix a typo in wpa_scan_result_compar()

A typo in wpa_scan_result_compar() caused wrong scan results sorting
(and wrong roaming decision). This fixes a copy-paste regression
introduced by commit a1b790eb9d7514d1a6e0582a07f695a1564caa59 ('Select
AP based on estimated maximum throughput').

Signed-off-by: Maital Hahn <maitalm@ti.com>

wpa_supplicant/scan.c

@@ -1679,7 +1679,7 @@ static int wpa_scan_result_compar(const void *a, const void *b)
 		snr_a_full = wa->snr;
 		snr_a = MIN(wa->snr, GREAT_SNR);
 		snr_b_full = wb->snr;
-		snr_b = MIN(wa->snr, GREAT_SNR);
+		snr_b = MIN(wb->snr, GREAT_SNR);
 	} else {
 		/* Level is not in dBm, so we can't calculate
 		 * SNR. Just use raw level (units unknown). */