AMDGPU: Mark all unspecified CC functions in tests as amdgpu_kernel

Currently the default C calling convention functions are treated
the same as compute kernels. Make this explicit so the default
calling convention can be changed to a non-kernel.

Converted with perl -pi -e 's/define void/define amdgpu_kernel void/'
on the relevant test directories (and undoing in one place that actually
wanted a non-kernel).

llvm-svn: 298444
diff --git a/llvm/test/CodeGen/AMDGPU/empty-function.ll b/llvm/test/CodeGen/AMDGPU/empty-function.ll
index a060900..1231cb4 100644
--- a/llvm/test/CodeGen/AMDGPU/empty-function.ll
+++ b/llvm/test/CodeGen/AMDGPU/empty-function.ll
@@ -7,14 +7,14 @@
 ; SI-LABEL: {{^}}empty_function_ret:
 ; SI: s_endpgm
 ; SI: codeLenInByte = 4
-define void @empty_function_ret() #0 {
+define amdgpu_kernel void @empty_function_ret() #0 {
   ret void
 }
 
 ; SI: .text
 ; SI-LABEL: {{^}}empty_function_unreachable:
 ; SI: codeLenInByte = 0
-define void @empty_function_unreachable() #0 {
+define amdgpu_kernel void @empty_function_unreachable() #0 {
   unreachable
 }