roll: pigweed, pw_toolchain: pw_toolchain: Register Cortex-M7 toolchain

We apparently added this toolchain in http://pwrev.dev/183160, but
forgot to register it! This is pretty confusing, because we register all
the other Cortex-M toolchains.

See
https://discord.com/channels/691686718377558037/735952592894689350/1269916490614964224
for an example of someone affected by this.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/227598
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>

https://pigweed.googlesource.com/pigweed/pigweed
pigweed, pw_toolchain Rolled-Commits: 71c4c844f102502..b780dd700cfaf17
Roller-URL: https://ci.chromium.org/b/8740420305671349169
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I512b1b21dfd4eefb31e8083e062cfdae8d00bbce
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/quickstart/bazel/+/227691
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
diff --git a/WORKSPACE b/WORKSPACE
index 41d0186..a78d084 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -83,18 +83,18 @@
 git_repository(
     name = "pigweed",
     # ROLL: Warning: this entry is automatically updated.
-    # ROLL: Last updated 2024-08-04.
-    # ROLL: By https://cr-buildbucket.appspot.com/build/8740497548058710849.
-    commit = "71c4c844f1025025474e989c4c25ca201c5d3afc",
+    # ROLL: Last updated 2024-08-05.
+    # ROLL: By https://cr-buildbucket.appspot.com/build/8740420305671349169.
+    commit = "b780dd700cfaf17a735c1d205ad8dab33136fc18",
     remote = "https://pigweed.googlesource.com/pigweed/pigweed.git",
 )
 
 git_repository(
     name = "pw_toolchain",
     # ROLL: Warning: this entry is automatically updated.
-    # ROLL: Last updated 2024-08-04.
-    # ROLL: By https://cr-buildbucket.appspot.com/build/8740497548058710849.
-    commit = "71c4c844f1025025474e989c4c25ca201c5d3afc",
+    # ROLL: Last updated 2024-08-05.
+    # ROLL: By https://cr-buildbucket.appspot.com/build/8740420305671349169.
+    commit = "b780dd700cfaf17a735c1d205ad8dab33136fc18",
     remote = "https://pigweed.googlesource.com/pigweed/pigweed.git",
     strip_prefix = "pw_toolchain_bazel",
 )