BACKPORT: usb: xhci: Fix TRB transfer length macro used for Event TRB.

BACKPORT: usb: xhci: Fix TRB transfer length macro used for Event TRB.

Use proper macro while extracting TRB transfer length from
Transfer event TRBs. Adding a macro EVENT_TRB_LEN (bits 0:23)
for the same, and use it instead of TRB_LEN (bits 0:16) in
case of event TRBs.

This patch should be backported to kernels as old as 2.6.31, that
contain the commit b10de142119a676552df3f0d2e3a9d647036c26a "USB: xhci:
Bulk transfer support".  This patch will have issues applying to older
kernels.

Signed-off-by: Vivek gautam <gautam.vivek@samsung.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
BUG=chrome-os-partner:18460
TEST=on Spring EVT board, use camera preview and get an image.

Change-Id: Id33eaf62d67edcc5c79a187dd415b914133a58d3
Reviewed-on: https://gerrit.chromium.org/gerrit/47141
Tested-by: Vincent Palatin <vpalatin@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Commit-Queue: Vincent Palatin <vpalatin@chromium.org>