buildroot

linux-firmware: bump version

Bump to the latest (as of this writing) linux-firmware git version.
This adds support for newer iwlwifi firmware versions that are required
for newer kernel series.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>