mhi: core: Remove verbose log from threaded interrupt handler

Verbose log out side the write lock is getting preempted by
other irq and incorrectly identified that mhi irq hogging
cpu when the other irq is responsible for that. Remove
verbose logging from mhi threaded irq which is not really
needed.

Change-Id: I1608d64a43600e662de9076642d0097e31b01a46
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>