misc: Delete the now unnecessary create methods.

Most create() methods are no longer necessary. This change deletes them,
and occasionally moves some code from them into the constructors they
call.

Change-Id: Icbab29ba280144b892f9b12fac9e29a0839477e5
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/36536
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/dev/net/etherdump.cc

@@ -100,9 +100,3 @@ EtherDump::dumpPacket(EthPacketPtr &packet)
     stream->write(reinterpret_cast<char *>(packet->data), pkthdr.caplen);
     stream->flush();
 }
-
-EtherDump *
-EtherDumpParams::create() const
-{
-    return new EtherDump(*this);
-}