Set the correct GMEM and istore sizes for A320 on APQ8064.
The more GMEM we have the happier we are, so the code will
work with 256K, but it will be better with 512K. For the
instruction store the size is important during GPU snapshot
and postmortem dump. Also, the size of each instruction is
different on A3XX so remove the hard coded constants and
add a GPU specific size variable.
This GPU has a larger instruction store, so more memory
needs to be reserved for saving shader state when context
switching.
The initial vertex and pixel partitioning of the
instruction store also needs to be different.
