misc: Collapse all uses of DTRACE(x) to Debug::x.

Also mark the DTRACE macro as deprecated.

Change-Id: I99d9a9544b539117b375186e3e425d73d3c5cab7
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/45009
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>

src/dev/serial/terminal.cc

@@ -324,7 +324,7 @@ void
 Terminal::writeData(uint8_t c)
 {
 #if TRACING_ON == 1
-    if (DTRACE(Terminal)) {
+    if (Debug::Terminal) {
         static char last = '\0';
 
         if ((c != '\n' && c != '\r') || (last != '\n' && last != '\r')) {