[AArch64] Move CALL_RVMARKER definition after CALL.

This is a NFC with respect to the generated code. But it fixes a crash
when using -debug, because of the position in the enum CALL_RVMARKER
nodes were treated as memops. That caused a crash when printing
CALL_RVMARKER nodes.

llvm/lib/Target/AArch64/AArch64ISelLowering.h

@@ -51,6 +51,10 @@ enum NodeType : unsigned {
   WrapperLarge, // 4-instruction MOVZ/MOVK sequence for 64-bit addresses.
   CALL,         // Function call.
 
+  // Pseudo for a OBJC call that gets emitted together with a special `mov
+  // x29, x29` marker instruction.
+  CALL_RVMARKER,
+
   // Produces the full sequence of instructions for getting the thread pointer
   // offset of a variable into X0, using the TLSDesc model.
   TLSDESC_CALLSEQ,
@@ -429,10 +433,6 @@ enum NodeType : unsigned {
   LDP,
   STP,
   STNP,
-
-  // Pseudo for a OBJC call that gets emitted together with a special `mov
-  // x29, x29` marker instruction.
-  CALL_RVMARKER
 };
 
 } // end namespace AArch64ISD