[NFC] Missing riscv-registered-target in the test (#172596)

diff --git a/clang/test/PCH/riscv-rvv-vectors.c b/clang/test/PCH/riscv-rvv-vectors.c
index 0ffd82b..253513f 100644
--- a/clang/test/PCH/riscv-rvv-vectors.c
+++ b/clang/test/PCH/riscv-rvv-vectors.c
@@ -1,3 +1,4 @@
+// REQUIRES: riscv-registered-target
 // RUN: rm -rf %t
 // RUN: split-file %s %t