wpa_supplicant: Fix configuration parsing error for tx_queue_*

In the original flow, after hostapd_config_tx_queue() successfully
parses a tx_queue variable, wpa_config_process_global() would not return
immediately. Then it would print out "unknown global field" later and set
return val to -1.

Return success (0) after hostapd_config_tx_queue() successfully parses a
tx_queue variable to fix this.

Fixes: 790026c3da ("Allow TX queue parameters to be configured for wpa_supplicant AP/P2P GO")
Signed-off-by: Michael Lee <michael-cy.lee@mediatek.com>

wpa_supplicant/config.c

@@ -5620,6 +5620,7 @@ int wpa_config_process_global(struct wpa_config *config, char *pos, int line)
 					   line);
 				return -1;
 			}
+			return ret;
 		}
 
 		if (os_strncmp(pos, "wmm_ac_", 7) == 0) {