Revert "HACK: usb: gadget: fix android composite driver build"

This reverts commit 0fdc146d.

In preparation for merging lsk-v3.18-15.07-android into msm-3.18,
revert LSK changes to the android composite gadget driver which were
already present in another form on msm-3.18.

This avoids resolution of some fairly nasty merge conflicts caused by
msm-3.18 having slight different versions of the changes, and issues
due to additional changes to this code in msm-3.18 that are missing
in LSK.

Change-Id: I5e015565c56c3e1060326b265c0c386d54311252
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>