Revert "omap4-common: enable swapping to zram"

Disable zram for now, until backported from 3.13.

This reverts commit eeb0af687e8fe3ea72e13eef6b677b1a910f42c7.

Conflicts:
	root/fstab.mapphone_cdma
	root/fstab.mapphone_umts

Change-Id: Ib9858c1c88410995bad778066bc7452e782e0b0a