lmkd: add sys_resource

Addresses the following denial / error:

E/lowmemorykiller(  187): Error writing /proc/1148/oom_adj; errno=13

[  118.264668] type=1400 audit(947231128.209:140): avc:  denied { sys_resource } for  pid=187 comm="lmkd" capability=24 scontext=u:r:lmkd:s0 tcontext=u:r:lmkd:s0 tclass=capability

Change-Id: Ief2a7ead9cdd8a33e3add111ee99f7a29c12a3f2