Disable riscv in all Bazel mixed builds

Bug: 262192655
Test: CI
Change-Id: Ie46eb661f968396f40458d674897b554be8d47c3
diff --git a/android/bazel.go b/android/bazel.go
index 782632b..1a71def 100644
--- a/android/bazel.go
+++ b/android/bazel.go
@@ -357,6 +357,7 @@
 	mixedBuildEnabled := ctx.Config().IsMixedBuildsEnabled() &&
 		ctx.Os() != Windows && // Windows toolchains are not currently supported.
 		ctx.Os() != LinuxBionic && // Linux Bionic toolchains are not currently supported.
+		ctx.Arch().ArchType != Riscv64 && // TODO(b/262192655) Riscv64 toolchains are not currently supported.
 		module.Enabled() &&
 		convertedToBazel(ctx, module) &&
 		ctx.Config().BazelContext.IsModuleNameAllowed(module.Name(), withinApex)