Ignore child mtp devices
Review Request #121446 - Created Dec. 11, 2014 and discarded
When an mtp device has child usb devices (for example when you plug an android phone with debugging), these childs usbs are mark as MTP but we can't really access them.
According to the udev rules installed by libmtp, an alias devlink is added to the actual device, so this patch adds a filter for that.
Tested with 3 different devices, 2 of them android with and withtout debug and it worked fine (plasma shows only 1 working mtp device instead of 3)