g2: Cleanup BoardConfigCommon.mk

Who the hell thought some of these flags were a good idea? There's
stuff in here from ARMv5 (I mean, really???). Trash all the
useless flags and configs and use something that vaguely resembles
the makefile for a device from this decade...

Change-Id: I5faa32cd2ddfcfadb45253946923e1667e449cc2
g2: Switch to NEON and VFP v4

Change-Id: I60707ff338270b4dc693227e0b354ff894092e84
Merge pull request #2 from lg-devs/cm-12.0

Update