mem: Delete the MessageReq and MessageResp memory commands.

Now that Message*Port is gone, there are no users of these two memory
commands. They can now be deleted, simplifying the memory system
slightly.

Change-Id: If157dade4a3fb2610756c2ee81dc0c3fac670a26
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20824
Reviewed-by: Gabe Black <gabeblack@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/mem/packet.cc

@@ -180,11 +180,8 @@ MemCmd::commandInfo[] =
     /* SwapResp -- for Swap ldstub type operations */
     { SET4(IsRead, IsWrite, IsResponse, HasData),
             InvalidCmd, "SwapResp" },
-    /* IntReq -- for interrupts */
-    { SET4(IsWrite, IsRequest, NeedsResponse, HasData),
-        MessageResp, "MessageReq" },
-    /* IntResp -- for interrupts */
-    { SET2(IsWrite, IsResponse), InvalidCmd, "MessageResp" },
+    { 0, InvalidCmd, "Deprecated_MessageReq" },
+    { 0, InvalidCmd, "Deprecated_MessageResp" },
     /* MemFenceReq -- for synchronization requests */
     {SET2(IsRequest, NeedsResponse), MemFenceResp, "MemFenceReq"},
     /* MemFenceResp -- for synchronization responses */

src/mem/packet.hh

@@ -115,9 +115,8 @@ class MemCmd
         StoreCondResp,
         SwapReq,
         SwapResp,
-        MessageReq,
-        MessageResp,
-        MemFenceReq,
+        // MessageReq and MessageResp are deprecated.
+        MemFenceReq = SwapResp + 3,
         MemFenceResp,
         CleanSharedReq,
         CleanSharedResp,