roll: pigweed pw_spi_rp2040: Minor cleanup

* Remove unused LazyInit(): This private method did nothing and was
  never called. We move the comment about spi_init() into docs.rst.

* Remove unused init_status_: This private member was never used.

* Remove unused bits_per_word_: This private member was only written,
  and never read -- except for where it was just set.

* Move constructor initialization list into class definition. This has
  the potential to improve codegen.

Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/236233
Original-Revision: 783b29c23dd865fde344501c1b99adba4c956479

Rolled-Repo: https://pigweed.googlesource.com/pigweed/pigweed
Rolled-Commits: 846bb7d3672e94..783b29c23dd865
Roller-URL: https://ci.chromium.org/b/8735815676429092673
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: Idad3655e511e0ca3dd1d9d90eb0d3be39738fb4a
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/quickstart/bazel/+/237892
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/MODULE.bazel b/MODULE.bazel
index 8a55336..60cb947 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -48,18 +48,18 @@
 git_override(
     module_name = "pigweed",
     # ROLL: Warning: this entry is automatically updated.
-    # ROLL: Last updated 2024-09-24.
-    # ROLL: By https://cr-buildbucket.appspot.com/build/8735871550182583937.
-    commit = "846bb7d3672e94c13451bec81098d3304d8395a9",
+    # ROLL: Last updated 2024-09-25.
+    # ROLL: By https://cr-buildbucket.appspot.com/build/8735815676429092673.
+    commit = "783b29c23dd865fde344501c1b99adba4c956479",
     remote = "https://pigweed.googlesource.com/pigweed/pigweed",
 )
 
 git_override(
     module_name = "pw_toolchain",
     # ROLL: Warning: this entry is automatically updated.
-    # ROLL: Last updated 2024-09-24.
-    # ROLL: By https://cr-buildbucket.appspot.com/build/8735871550182583937.
-    commit = "846bb7d3672e94c13451bec81098d3304d8395a9",
+    # ROLL: Last updated 2024-09-25.
+    # ROLL: By https://cr-buildbucket.appspot.com/build/8735815676429092673.
+    commit = "783b29c23dd865fde344501c1b99adba4c956479",
     remote = "https://pigweed.googlesource.com/pigweed/pigweed",
     strip_prefix = "pw_toolchain_bazel",
 )