This commit adds support for creating and destroying MHI devices. The
MHI devices binds to the MHI channels and are used to transfer data
between MHI host and client device.

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>
[mani: splitted from 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/20200220095854.4804-5-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>