powerpc/85xx: add support the ePAPR "phandle" property

powerpc/85xx: add support the ePAPR "phandle" property

The ePAPR specification says that phandle properties should be called
"phandle", and not "linux,phandle".  To facilitate the migration from
"linux,phandle" to "phandle", we update fdt_qportal() to use the new
function, fdt_create_phandle().  This function abstracts the creation of
phandle properties.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>