disp: msm: sde: make mnoc icc paths optional

ICC frameworks may not be enabled for all the OS
environments. SDE is expected to work in the environments
where ICC paths are not defined e.g Trusted VM. Except
mnoc bus, SDE is keeping all the other paths optional.
This change adds mnoc bus to the optional list.

Change-Id: I1e3d31a3b0f49fb32041bc7e2192b014f6497267
Signed-off-by: Jeykumar Sankaran <jsanka@codeaurora.org>