usb: gadget: add support for multiple LUNs

Change-Id: I9e79153dbcbff9e39c4f57c2345e9296eec3a2cc
msm: HTC: add config option to support two UMS LUN paths

CONFIG_HTC_UMS_TWO_LUN:
 n = 1 LUN
 y = 2 LUN

Change-Id: I67bf099c277d45f8ab18639fbc4ff887ee319466
msm: HTC: fighter: enable two UMS LUN paths

fighter_defconfig regenerated and CONFIG_HTC_UMS_TWO_LUN set true.

Change-Id: I1be937cfa40d1c699bd047e72a181def1f50815a