bus: mhi: core: Add const qualifier to MHI config information

bus: mhi: core: Add const qualifier to MHI config information

MHI channel, event and controller config data needs to be
treated read only information. Add const qualifier to make
sure config information passed by MHI controller is not
modified by MHI core driver.

Suggested-by: Kalle Valo <kvalo@codeaurora.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200929175218.8178-12-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>