Staging: csr: update to version 5.1.0 of the driver

This brings the in-kernel driver up to the level of the
csr-linux-wifi-5.1.0-oss.tar.gz tarball.

Cc: Mikko Virkkilä <mikko.virkkila@bluegiga.com>
Cc: Lauri Hintsala <Lauri.Hintsala@bluegiga.com>
Cc: Riku Mettälä <riku.mettala@bluegiga.com>
Cc: Veli-Pekka Peltola <veli-pekka.peltola@bluegiga.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>