fbdev: msm: Do SMMU attach before buffer map

Initialize overlay, do splash clean up and smmu attach
before calling dma_buf apis to attach/map the source
buffers. This makes sure iommu_dma_ops are used for
buffer attach/map instead of swiotlb_dma_ops.

Change-Id: I7d7d75cf0e21861eafc26d7b5ac0e185d2bfe033
Signed-off-by: Nirmal Abraham <nabrah@codeaurora.org>