usb: hsic: Add USB HSIC gadget driver

This change adds USB HSIC gadget functionality.

This snapshot is taken as of msm-3.18 'commit cd0018e74c9e
("qseecom: Backport qseecom listener changes to kernel-3.18")'.

Change-Id: Ibdb1c133e23afed017809058dffb553a83d94c99
Signed-off-by: Prasadarao Durvasula <pdurvasu@codeaurora.org>
Signed-off-by: Sivasri Kumar Vanka <sivasri@codeaurora.org>