Make crypto/buildinf.h depend on configdata.pm rather than Makefile

Depending on Makefile meant that a new attempt to rebuild the Makefile
with "new" dependency data was done all the time, uncontrolled.  Better
to depend on configdata.pm, which truly only changes with reconfiguration.

Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Ben Laurie <ben@openssl.org>