MFC r360126, r360132: Change kern.evdev.rcpt_mask to 12 by default

Original commit messages:
Change kern.evdev.rcpt_mask from 3 to 12 by default. This makes us much
more evdev-friendly, and will prevent everyone using xorg and wayland with
evdev devices (the default) from needing to change this locally.

powerpc32 still uses the old value for the keyboard part, becaues the adb
keyboard driver used there is not evdev compatible.

In r360126, I meant to have a different mask only on powerpc, not powerpc64.
Update the check to check that we're not compiling for powerpc64.

Approved by: wulf (implicit, mfc)
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D24370