Lower the RAM requirement for hardware acceleration

There are legacy devices with about 365 MBytes of RAM
available to the kernel (HDPI with 512 MB RAM onboard).
Lowering the requirement value for available RAM allows
these devices to also use hardware acceleration, thus
making the UI a lot more responsive and fixing bugs like
this: https://dl.dropboxusercontent.com/u/16268774/Screenshots/Phone/Screenshot_2013-10-07-01-27-45.png
(notice the "shadow" is missing)

Change-Id: I1657ee2e52563c4e6c381a8ebb6c102a4c193918
Merge "Lower the RAM requirement for hardware acceleration" into android-4.3