ptx: fix parameter order that is reversed

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127874 91177308-0d34-0410-b5e6-96231b3b80d8

test/CodeGen/PTX/parameter-order.ll

@@ -0,0 +1,8 @@
+; RUN: llc < %s -march=ptx | FileCheck %s
+
+; CHECK: .func (.reg .u32 r0) test_parameter_order (.reg .u32 r1, .reg .u32 r2)
+define ptx_device i32 @test_parameter_order(i32 %x, i32 %y) {
+; CHECK: sub.u32 r0, r1, r2
+	%z = sub i32 %x, %y
+	ret i32 %z
+}