mem: Compile tracePacket only when TRACING_ON is defined

If TRACING_ON is not defined (e.g. when building gem5.fast), clang
compilations will fail reporting an unused function.

Change-Id: I959dba6e9fcf74b951e16365077939ae4d4ef924
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/14975
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
1 file changed