USB: gadget: ci13xxx_msm: Print timestamps similar to kernel logbuf

Currently timestamps in events are printed in microsecs which we
can't corelate with kernel logbuf timestamps. Hence print timestamps
in similar format as kernel logbuf.

CRs-Fixed: 720016
Change-Id: I5d2dba9e0723be8cc1bfb784b8d5f4ebfe79e464
Signed-off-by: Vijayavardhan Vennapusa <vvreddy@codeaurora.org>