msm: ipa: gsi: mhi: Couple of code changes

Couple of code changes,

 - Enable IPC logging for MHI driver.
   IPC logging was missed to enable on mhi driver,
   enable it.

 - Configure appropriate polling mode bit for MHI ep.

   A. For MHI --> IPA pipe:
      When resuming due to transition to M0,
      set the polling mode bit to 0. In other cases,
      restore it's value form when you stopped the channel.

   B. For IPA-->MHI pipe:
      Always restore the polling mode bit.

Change-Id: Ibc203e8c9dc8d05107a5eba396c76e29c1646479
Signed-off-by: Mohammed Javid <mjavid@codeaurora.org>