msm: kgsl: Move memory pool initialization to the KGSL core

In the code the memory pools are generic. They are stored in global memory
and none of the APIs take a device handle, yet the device tree description
has traditionally been device specific and as such the pools were set up
at device initialization time.

This is not needed as we can safely look up the memory pools node from the
compatible string at any point. Make the memory pools completely generic
and initialize them with the rest of the KGSL core. This clears the way
to move the memory definitions out of the device and into the top level
soc in the device tree, but since we are using the compatible string
that isn't strictly necessary.

Change-Id: Ic0dedbad687b9581f0e40142644ed19ee069d54d
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>