Build riscv64 with thin LTO

Depends on: https://android-review.git.corp.google.com/c/platform/system/libhwbinder/+/2336346

Bug: b/254713216
Change-Id: Id750cab796ddf8c180fa0570e46cab0161788974
diff --git a/cc/lto.go b/cc/lto.go
index 1afa1dd..581856b 100644
--- a/cc/lto.go
+++ b/cc/lto.go
@@ -91,11 +91,6 @@
 		return flags
 	}
 
-	// TODO(b/254713216): LTO doesn't work on riscv64 yet.
-	if ctx.Arch().ArchType == android.Riscv64 {
-		return flags
-	}
-
 	if lto.LTO(ctx) {
 		var ltoCFlag string
 		var ltoLdFlag string