rndis: hack to get stable MAC addr

Avoid using randomly assigned MAC addr, so devices IP address doesn't
change on each boot, and so we don't confuse NetworkManager about
settings.
slub: workaround for corruption in mm_struct and task_struct pools

I'm not sure where the root issue is, but somehow we get some corruption
in these pools (even without using graphics/freedreno).  Making
everything cacheline aligned seems to avoid the problems.
tenderloin_rob_defconfig updates

1) use 2g/2g split, to work-around fact that current kgsl kernel driver
   is using vmalloc for graphics buffers, and w/ 3g vmsplit we quickly
   start to run out of memory
2) disable android ram-console and other android drivers.. they seem to
   be one remaining source of memory corruption, so disable them until
   that is solved.  (The ram-console is the only one of the android
   staging drivers that is actually useful.  Others are unneeded
   anyways.)
3) enable some things needed by systemd, like CONFIG_FANOTIFY.
4) disable CIFS, since that is easier than fixing the compile errors
   with modern gcc.