maple: fix device detection

The maple bus driver that went into the kernel mainline in September 2007
contained some bugs which were revealed by the update of the kobj code
for the current release series. Unfortunately those bugs also helped
ensure maple devices were properly detected. This patch (against the
current git) now ensures that devices are properly detected again.

(A previous attempt to fix this by delaying initialisation only partially
 fixed this - as became apparent when the bus was fully loaded)

Signed-off-by: Adrian McMenamin <adrian@mcmen.demon.co.uk>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>