usb: gadget: f_mtp: Change the icon to camera for PTP composition

The existing code shows the phone icon in 'My Computer' of windows host,
for PTP composition.
Create a new Extended Configuration Descriptor for PTP composition and
update the compatibleID to display a camera icon for PTP composition.

Change-Id: If286c5b80874a95be0b5ecc533d0e5c7a14f39d3
Signed-off-by: Azhar Shaikh <azhars@codeaurora.org>
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>