msm: 8660: Make SF heap in ION same as the corresponding pmem heap

While normal UI composition through the GPU will work with 24 MB
in ICS, the memory requirements are higher and we will keep
falling back to the system heap even before bootup is complete.
This will reduce performance since comp. bypass will not work with
the system heap. Make the SF heap size the same as it was with pmem
so that we do not run into this issue with ION.

Change-Id: If6bca8d1f2d532d04638deb0ed0c5fa411740cc9
Signed-off-by: Naseer Ahmed <naseer@codeaurora.org>