mhi: core: Dump cookie value upon assert

Upon assert cookie value does not seem to match
with the cookie present in the event ring. Hence
dump the value to compare the difference for
debugging purpose. Also update the assert macro
to allow printing values.

Change-Id: I19ad539d09084d55c154f5b2d927e1f9e91a671f
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>