bus: mhi: core: Remove the system error worker thread

bus: mhi: core: Remove the system error worker thread

Remove the system error worker thread and instead have the
execution environment worker handle that transition to serialize
processing and avoid any possible race conditions during
shutdown.

Signed-off-by: Hemant Kumar <hemantk@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/20200521170249.21795-10-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>