[third_party/pigweed] Roll 7 commits

a9a64a72393ed20 pw_stream_uart_mcuxpresso: Use clock tree
57310630f125c37 pw_clock_tree: Introduce ElementController class
1a672e2605ac5a4 pw_clock_tree_mcuxpresso: Fix source set name and
1d491c30feb54ee pw_clock_tree: Fix source set name and visibility
aaa553c8693be3d pw_stream_uart_mcuxpresso: DMA stream example
e8dcc48f4c5e8aa mimxrt595: Upgrade to SDK_2_14_0_EVK-MIMXRT59
1f6ad3a910c7cb0 pw_multibuf: SimpleAllocatorForTest

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: 7bb5a76cced7e77..a9a64a72393ed20
Roller-URL: https://ci.chromium.org/b/8746388897609133457
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I7ec84a7af0880268ad9c0596671f0df736308506
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/examples/+/213031
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index 7bb5a76..a9a64a7 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit 7bb5a76cced7e7774e14a1246c7fc674a3850b34
+Subproject commit a9a64a72393ed200e8498bd4e1a33f58fc337d04