msm: mhi_dev: Update msi logic

Some times HOST might set msi capability bit little late during
boot up. Update msi logic such that MHI driver initialization
happens irrespective of the state of msi capability bit.

Change-Id: I02811efa9ed84f9fd4dbe9763087f109e61fae56
Signed-off-by: Rama Krishna Phani A <rphani@codeaurora.org>