board/qemu/microblaze: convert kernel patch to git format

Convert the patch for microblaze kernel added for kernel 3.14 by
Waldemar to git format.

Note: the Waldemar Sob line is missing in the original patch:
fa279854

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Cc: Waldemar Brodkorb <wbx@openadk.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>