Make pow2ceil() and pow2floor() inline

Make pow2ceil() and pow2floor() inline

Since the pow2floor() function is now used in a hot code path,
make it inline; for consistency, provide pow2ceil() as an inline
function too.

Because these functions use ctz64() we have to put the inline
versions into host-utils.h, so they have access to ctz64(),
and move the inline is_power_of_2() along with them.

We then need to include host-utils.h from qemu-common.h so that
the files which use these functions via qemu-common.h still have
access to them.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1437741192-20955-7-git-send-email-peter.maydell@linaro.org