[roll third_party/pigweed] pw_rpc_transport: Add simple_framing Soong rule

Add Soong build rule for the pw_rpc_transport_simple_framing library.

Test: In Android, pulled change into `external/pigweed`, built project
 depending on this library, and built all of Android with `m`.
Original-Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/165350

https://pigweed.googlesource.com/pigweed/pigweed
third_party/pigweed Rolled-Commits: aa9cec4c76bcbaa..46b09091f2c1c77
Roller-URL: https://ci.chromium.org/b/8772768200223048865
GitWatcher: ignore
CQ-Do-Not-Cancel-Tryjobs: true
Change-Id: I3f89f963cc7bff67c4c6c0eddc996b1819538a5a
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/experimental/+/165850
Commit-Queue: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
Bot-Commit: Pigweed Roller <pigweed-roller@pigweed-service-accounts.iam.gserviceaccount.com>
diff --git a/third_party/pigweed b/third_party/pigweed
index aa9cec4..46b0909 160000
--- a/third_party/pigweed
+++ b/third_party/pigweed
@@ -1 +1 @@
-Subproject commit aa9cec4c76bcbaa3c5393d22a95dc89d5de9e05a
+Subproject commit 46b09091f2c1c77fc735287aed045dc2aa8d4fec