misc: Remove typedef (struct|enum) Foo in cpp files.

In C, to refer to a type without a struct or enum tag on the type, you
need to typedef it like this:

typedef struct
{
} Foo;

Foo foo;

In C++, this is unnecessary:

struct Foo
{
};

Foo foo;

Remove all of the first form in C++ files and replace them with the
second form.

Change-Id: I37cc0d63b2777466dc6cc51eb5a3201de2e2cf43
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/46199
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
23 files changed