bus: mhi: core: Improve debug logs for loading firmware

Add log messages to track boot flow errors and timeouts in SBL or AMSS
firmware loading to aid in debug.

Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: Jeffrey Hugo <jhugo@codeaurora.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20200521170249.21795-8-manivannan.sadhasivam@linaro.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>