[roll] Roll fuchsia [zbi-format] Prepare cpu.h for generation from FIDL

This change ~cosmetically updates the CPU topology definitions for
easier FIDL generation (or at least uniformity for the legacy cases that
we will not be generating), doing the following:
* C enums are replaced by the usual macro constants (we do not support
generation of C enums);
* s/ZBI_TOPOLOGY_ARCH/ZBI_TOPOLOGY_ARCHITECTURE for a more official name
* s/ZBI_TOPOLOGY_PROCESSOR/ZBI_TOPOLOGY_PROCESSOR_FLAGS for clarity
* s/x86/x64, s/arm/arm64, s/riscv/riscv64 to use the more official
architecture names (as the kernel item type already do)

This change preserves the ABI of the v2 definitions, leaving the
remaining planned ABI update for a future change.

Original-Bug: 111453
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/868169
Original-Revision: 4ec01d65c42c913769a79950fc20b38183196614
GitOrigin-RevId: 231280bee832f355033211b71d96d05787691170
Change-Id: I2d79506b2b93bc27e4adaeb9110cb567cc955c4d
diff --git a/stem b/stem
index 238883d..d1d175f 100644
--- a/stem
+++ b/stem
@@ -11,7 +11,7 @@
              githooks="integration/git-hooks"
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="bb4068d93a864f8854dbee6c0de2ced2e8cfcee8"/>
+             revision="4ec01d65c42c913769a79950fc20b38183196614"/>
   </projects>
   <hooks>
     <hook name="install-environment"