Allow toggle of MTP debug

Via command line in TWRP:
twrp set tw_mtp_debug 1

This will enable debugging for MTP. You will need to disable and
re-enable MTP in order to see the debug logging.

Change-Id: Ia7bb0c584e10a4322b65ecf80a67ed7ee836b38e
diff --git a/partitionmanager.cpp b/partitionmanager.cpp
index 59451e3..a8b61c3 100644
--- a/partitionmanager.cpp
+++ b/partitionmanager.cpp
@@ -2171,7 +2171,10 @@
 	TWFunc::write_file("/sys/class/android_usb/android0/idProduct", productstr);
 	property_set("sys.usb.config", "mtp,adb");
 	std::vector<TWPartition*>::iterator iter;
-	twrpMtp *mtp = new twrpMtp();
+	/* To enable MTP debug, use the twrp command line feature to
+	 * twrp set tw_mtp_debug 1
+	 */
+	twrpMtp *mtp = new twrpMtp(DataManager::GetIntValue("tw_mtp_debug"));
 	for (iter = Partitions.begin(); iter != Partitions.end(); iter++) {
 		if ((*iter)->Is_Storage && (*iter)->Is_Present && (*iter)->Mount(false)) {
 			printf("twrp mtpid: %d\n", (*iter)->mtpid);