msm: msm_bus: Fix the check for gateway fabrics

A bug due to which routing to some of the cpss slaves
was broken is fixed by avoiding an unnecessary check.
This should also make routing to other slaves faster.

Change-Id: I4d276857c040e1c5ce3df5360340405282b40084
Signed-off-by: Gagan Mac <gmac@codeaurora.org>