firmware: qcom: fix qsee_log issue

To fix corrupted qsee_log issue, instead of sub-allocating cached
memory from default shmbridge pool, change back to allocate uncached
memory from dma_alloc_coherent for qsee_log buffer, and then create
shm bridge over this region.

Change-Id: I35339eacee35898ec81414077366ff8341caf79a
Signed-off-by: Zhen Kong <zkong@codeaurora.org>