tuna: enable KSM by default

Change-Id: Ica530b585fb9ec4c2f37dfb21cad5d06ce2b8b37
tuna: support performance profiles

powersave: 307mhz gpu
balanced: 384mhz gpu
performance: 512mhz gpu + 920mhz hispeed_freq (instead of the default 700mhz)

Change-Id: I4d3c9162599e18294130d8fb1c6a7437d201d9b0
default: balanced