kobject: convert parisc/pdc_stable to kobj_attr interface

This makes the code a bit simpler and and gets us one step closer to
deleting the deprecated subsys_attr code.

NOTE, this needs the next patch in the series in order to work properly.
This will build, but the sysfs files will not properly operate.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Thibaut VARENE <varenet@parisc-linux.org>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Grant Grundler <grundler@parisc-linux.org>
Cc: Kyle McMartin <kyle@parisc-linux.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>