misc: Remove the Net namespace

This namespace has gone through the deprecation period
and can now be removed.

Change-Id: Ia2e1ef1619f51a0d7c0da9c7b4a160cd88ed8a65
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/67366
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Richard Cooper <richard.cooper@arm.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>

src/base/inet.cc

@@ -54,7 +54,6 @@
 namespace gem5
 {
 
-GEM5_DEPRECATED_NAMESPACE(Net, networking);
 namespace networking
 {
 

src/base/inet.hh

@@ -68,7 +68,6 @@
 namespace gem5
 {
 
-GEM5_DEPRECATED_NAMESPACE(Net, networking);
 namespace networking
 {