hym8563: Fix 32-bit powerpc build

Depend on clknode_if.h in the module Makefile, so that it gets
explicitly built for the module. Also, reduce the #if guards to only
the new clock output code, and gate them on all powerpc, not just
powerpc64.

Fixes: 6b77d34f("HYM8563: Add support for clock output.")
Reviewed by: mmel
Differential Revision: https://reviews.freebsd.org/D57795