msm: msm_bus: Arbitrate IB for dual config masters

Arbitrate the IBs on nodes marked as dual config. This will prevent cases
where the last client's requests is always used to apply dual config rules.

Change-Id: I06f9a16e5f32c1cda7a5d04a72a6e5cf7dc9fae6
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>