Linux 4.4.231

BugLink: https://bugs.launchpad.net/bugs/1888690Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

Makefile

 VERSION = 4
 PATCHLEVEL = 4
-SUBLEVEL = 230
+SUBLEVEL = 231
 EXTRAVERSION =
 NAME = Blurry Fish Butt