test: fix hexagon build

Add a x86-registered-target requirement to the tests.

llvm-svn: 304739
diff --git a/llvm/test/Object/objc-imageinfo-elf.ll b/llvm/test/Object/objc-imageinfo-elf.ll
index 7979e01..f7484fa 100644
--- a/llvm/test/Object/objc-imageinfo-elf.ll
+++ b/llvm/test/Object/objc-imageinfo-elf.ll
@@ -1,4 +1,5 @@
 ; RUN: llc -mtriple x86_64-unknown-linux-gnu -filetype asm -o - %s | FileCheck %s
+; REQUIRES: x86-registered-target
 
 !llvm.module.flags = !{!0, !1, !2, !3}