Revert "remoteproc: qcom_q6v5_mss: map/unmap metadata region before/after use"

This reverts commit fc156629

.

This commit manages to do three API violations at once:

 - dereference the return value of dma_alloc_attrs with the
   DMA_ATTR_NO_KERNEL_MAPPING mapping, which is clearly forbidden and
   will do the wrong thing on various dma mapping implementations.  The
   fact that dma-direct uses a struct page as a cookie is an undocumented
   implementation detail
 - include dma-map-ops.h and use pgprot_dmacoherent despite a clear
   comment documenting that this is not acceptable
 - use of the VM_DMA_COHERENT for something that is not the dma-mapping
   code
 - use of VM_FLUSH_RESET_PERMS for vmap, while it is only supported for
   vmalloc

Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sibi Sankar <quic_sibis@quicinc.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230117085840.32356-6-quic_sibis@quicinc.com