fastmodel,dev: Rework the Int*Pin classes with Signal*Port.

These are largely compatibility wrappers around the Signal*Port
classes. The python versions of these types enforce more specific
compatibility, but on the c++ side the Signal*Port<bool> classes can
be used directly instead.

Change-Id: I1325074d0ed1c8fc6dfece5ac1ee33872cc4f5e3
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/66673
Maintainer: Gabe Black <gabeblack@google.com>
Reviewed-by: Yu-hsin Wang <yuhsingw@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/dev/SConscript

@@ -36,7 +36,6 @@ Source('dma_device.cc')
 Source('dma_virt_device.cc')
 
 SimObject('IntPin.py', sim_objects=[])
-Source('intpin.cc')
 
 SimObject('ResetPort.py', sim_objects=[])
 Source('reset_port.cc')