dmaengine: gpi: add GPI dmaengine driver snapshot

This change ports GPI dmaengine driver and its dependencies
from msm-4.14 to msm-4.19. All the files are as is from
msm-4.14. Additional changes were made to gpi driver to
support 4.19 kernel.

This gpi dmaengine driver snapshot is taken as of msm-4.14
commit: 7e09c6dae184
("Merge "diag: dci: Validate dci client entries prior read"").

Change-Id: Ib376405e5dced340d900a6938285847ad0ae7fbd
Signed-off-by: Vipin Deep Kaur <vkaur@codeaurora.org>