Add speaker equalizer and master switch to wolfson engine

1st try to add speaker equaliser in stweaks.
working, but values are not sticking after reboot.
Cause : eq_sp_gain and switch_master setting to 0 after reboot.
Merge pull request #15 from RohanAJoshi/patch-1

Add speaker equalizer and master switch to wolfson engine
Merge branch 'master' of github.com:temasek/stweaks_temasek into zram4