Place pinned memory as top priority.

Was doing some testing with buffer storage, coherent mapping, and pinned memory, and found out that Pinned Memory was faster on AMD cards even with coherent mapping on.  As such, if we move Pinned Memory to the first priority, it makes both NVIDIA and AMD get maximum performance.

On my Radeon HD5850, this is an 8% boost compared to before the performance regression.   This should probably be tested on a variety of graphics cards even though it's a minor change.  I do know it works fine on my GTX 760 and my Radeon HD5850.

Implementation is based on what Sonicadvance1 told me to do plus the fact only AMD supports Pinned Memory, no one else.