[roll] Roll fuchsia [platform-bus] Increase MMIO limit

We need a larger mmio limit for one of the GPU drivers.

Original-Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1739850
Original-Original-Revision: 9ce60ca790aa9d74cc74beae11376781e77daf5f
GitOrigin-RevId: 384cb0f0325c5f195546e54ba0041679c3dab8c4
Change-Id: Ic31226c42b2f5cfd39f56adb24eef930d8650d01

stem

diff --git a/stem b/stem
index 522c585..9bd664d 100644
--- a/stem
+++ b/stem
@@ -8,6 +8,6 @@
             manifest="manifests/platform"
             root=""
             remote="https://fuchsia.googlesource.com/fuchsia"
-            revision="a2c908f3583683839b77d67f7b560a451367d023"/>
+            revision="9ce60ca790aa9d74cc74beae11376781e77daf5f"/>
   </imports>
 </manifest>