Bug fix of 6GHz band channelization

Add the special case of 6G band channel 2.

Bug: 167426957
Test: manual test with 6GHz capable STA and AP
Change-Id: I0a74591d9102f76b2c3ab13b181825314eb82b92
diff --git a/hostapd/hidl/1.3/hostapd.cpp b/hostapd/hidl/1.3/hostapd.cpp
index 908473d..aa16e8c 100644
--- a/hostapd/hidl/1.3/hostapd.cpp
+++ b/hostapd/hidl/1.3/hostapd.cpp
@@ -196,6 +196,10 @@
 			// 160MHz channel
 			return 134;
 		}
+		if (channel == 2) {
+			// 20MHz channel
+			return 136;
+		}
 		// Error
 		return 0;
 	}