This commit adds support for transitioning the MHI states as a
part of the power management operations. Helpers functions are
provided for the state transitions, which will be consumed by the
actual power management routines.

This is based on the patch submitted by Sujeev Dias:
https://lkml.org/lkml/2018/7/9/989Signed-off-by: NSujeev Dias <sdias@codeaurora.org>
Signed-off-by: NSiddartha Mohanadoss <smohanad@codeaurora.org>
[jhugo: removed dma_zalloc_coherent() and fixed several bugs]
Signed-off-by: NJeffrey Hugo <jhugo@codeaurora.org>
[mani: splitted the pm patch and cleaned up for upstream]
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: NJeffrey Hugo <jhugo@codeaurora.org>
Tested-by: NJeffrey Hugo <jhugo@codeaurora.org>
Link: https://lore.kernel.org/r/20200220095854.4804-7-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>