marvell firwmare: update 8897 sdio firmware to 15.68.4.p7

Update 8897 uapsta firmware to latest version from Marvell.
This change is intended to bring us up-to-date with
Marvell's changes, and may improve stability issues with
reboot, reset, and/or suspend/resume.

While some tests from matfunc failed, we don't believe
this regresses significantly compared to p4.

BUG=chrome-os-partner:25980
TEST=network_WiFi_matfunc (some tests failed)

Change-Id: Iac63c08684e6255ce9dc5d85941878ba5ecbdc38
Previous-Reviewed-on: https://chromium-review.googlesource.com/187028
(cherry picked from commit b109afbcd1f2284cdef7d41a0ae06c9a1cb193c7)
Reviewed-on: https://chromium-review.googlesource.com/187999
Reviewed-by: mukesh agrawal <quiche@chromium.org>
Commit-Queue: mukesh agrawal <quiche@chromium.org>
Tested-by: mukesh agrawal <quiche@chromium.org>
1 file changed