ARM: dts: msm: Modify the bus width for MNOC BIMC gateway

The MNOC BIMC gateway at BIMC as a single port but two on the MNOC
side. Modify the buswidth at BIMC part of the gateway to account for
the discrepancy in the aggregation.

CRs-Fixed: 709226
Change-Id: I564f77514a89452515c8507de5d281c1193824a8
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>