msm: Remove memory reservation code

The memory reservation API used for allocate_contiguous_ebi is now
deprecated in favor of using standard kernel APIs such as
dma_alloc_coherent and CMA for reserving/allocating memory. Remove
lots of code.

Change-Id: I5a7c22cce6b4b772dc67d18029e40b4509d3ba40
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>