arch: Delete the decoder.hh switching header file.

Change-Id: I9340aa9fa87bcb03c27cb7107b6697ad96060dbe
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/52082
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
1 file changed