arch-x86: Use popCount from bitfields.hh.

Use popCount from bitfields.hh rather than call __builtin_popcountl
directly. That will ensure the instruction works whether or not that
builtin is available.

Change-Id: I947b35bb832b768936b489a58ee324adb8a90b5e
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/41354
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
1 file changed