bus: mhi: core: Move to an error state on mission mode failure

If the host receives a mission mode event and by the time it can get
to processing it, the register accesses fail implying a connectivity
error, MHI should move to an error state. This helps avoid longer wait
times from a synchronous power up perspective and accurately reflects
the MHI execution environment and power management states.

Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>