ISAPNP: fold isapnp_read_resources() back into isapnp_get_resources()

isapnp_get_resources() does very little besides call
isapnp_read_resources(), so just fold them back together.

Based on a patch by Rene Herman <rene.herman@gmail.com>

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>