usb: ci13xxx_udc: Add debug mask to control debug events

udc driver generates lot of debug events which quickly fills up
its circular event queue and override important events which are
required for debugging. Add debug mask support so that only the
events that match mask are captured discarding the rest. Debug
mask can be changed by module parameter and bit position
represents endpoint number.

Example: To capture 2 in endpoint events
echo -n 4 > /sys/module/ci13xxx_msm/parameters/ep_addr_txdbg_mask
To capture 3 out endpoint events
echo -n 8 > /sys/module/ci13xxx_msm/parameters/ep_addr_rxdbg_mask

Change-Id: Ia0383df67c85245a8f8415eee3d9b67f38ac2d1e
Signed-off-by: Vamsi Krishna <vskrishn@codeaurora.org>