autotools: Enable separate builddir by default

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
acpica: Add recipe for latest version

This is now used by multiple architectures and is useful when working
with firmware. I'd love to see more BSPs shipping working firmware
builds and this should bring us a step closer to that.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
bitbake.conf/base.bbclass: Drop PRINC support

PRINC is no longer needed since we have the PR service instead
which people should be using. Drop the PRINC code.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>