Add separate permission and group for access to MTP USB driver

Since the "usb" group and ACCESS_USB permission will be used by regular apps
to access USB devices in host mode, we need a separate permission for the
device side MTP driver.

Change-Id: Ibb546b8726d61e041fc7c273f71929624ad1575b
Signed-off-by: Mike Lockwood <lockwood@android.com>
diff --git a/rootdir/ueventd.rc b/rootdir/ueventd.rc
index a52bdda..a3ddf2b 100644
--- a/rootdir/ueventd.rc
+++ b/rootdir/ueventd.rc
@@ -69,7 +69,7 @@
 /dev/qmi1                 0640   radio      radio
 /dev/qmi2                 0640   radio      radio
 /dev/bus/usb/*            0660   root       usb
-/dev/mtp_usb              0660   root       usb
+/dev/mtp_usb              0660   root       mtp
 
 # CDMA radio interface MUX
 /dev/ts0710mux*           0640   radio      radio