defconfig: msm: Enable QTI composite gadget on sdxlemur

Enable config for qti_usb gadget to enable usb_composition
at boot time for sdxlemur.

Change-Id: Ifb4ca6001c9516aef491be878afca8b2acb10caf
Signed-off-by: Elson Roy Serrao <eserrao@codeaurora.org>