firmware: move firmware loader into its own directory

This will make it much easier to manage as we manage to
keep trimming componnents down into their own files to more
easily manage and maintain this codebase.

Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>