bus: mhi: core: Rely on accurate method to determine EDL mode

Relying on the current execution environment to determine if EDL
image was downloaded should not be done as the execution
environment can change at this point in error cases and we may
misread it. Instead, MHI can rely on the local 'fw_name' variable
as a safer alternative.

Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Link: https://lore.kernel.org/r/1617067704-28850-2-git-send-email-bbhatt@codeaurora.org


Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>