The recent patches adding partial support for POWER7 cpu emulation included
implementing the popcntd instruction.  The support for this was open coded,
but host-utils.h already included a function implementing an equivalent
population count function, which uses a gcc builtin (which can use special
host instructions) if available.

This patch makes the popcntd implementation use the existing, potentially
faster, implementation.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAlexander Graf <agraf@suse.de>