We currently rely on the recursive nature of devicetree bus probing to
obtain the region cell size specification from the parent device.
This blocks the possibility of creating a standalone console device
based on /chosen/stdout-path before probing the whole bus.
Fix by using fdt_parent() to locate the parent device at the point of
use within dt_ioremap().
Signed-off-by: Michael Brown <mcb30@ipxe.org>
bb2011241f