AMDGPU: Remove -mcpu=SI

Leftover from before amdgcn/r600 split.

llvm-svn: 310277
diff --git a/llvm/test/CodeGen/AMDGPU/insert_subreg.ll b/llvm/test/CodeGen/AMDGPU/insert_subreg.ll
index e895f27..dcf6fe8 100644
--- a/llvm/test/CodeGen/AMDGPU/insert_subreg.ll
+++ b/llvm/test/CodeGen/AMDGPU/insert_subreg.ll
@@ -1,4 +1,4 @@
-; RUN: llc -march=amdgcn -mcpu=SI -mattr=-promote-alloca -verify-machineinstrs < %s
+; RUN: llc -march=amdgcn -mcpu=tahiti -mattr=-promote-alloca -verify-machineinstrs < %s
 ; RUN: llc -march=amdgcn -mcpu=tonga -mattr=-promote-alloca -verify-machineinstrs < %s
 
 ; Test that INSERT_SUBREG instructions don't have non-register operands after