[PATCH] pnp: mpu401: adjust pnp_register_driver signature

This series of patches removes the assumption that pnp_register_driver()
returns the number of devices claimed.  Returning the count is unreliable
because devices may be hot-plugged in the future.  (Many devices don't support
hot-plug, of course, but PNP in general does.)

This changes the convention to "zero for success, or a negative error value,"
which matches pci_register_driver(), acpi_bus_register_driver(), and
platform_driver_register().

If drivers need to know the number of devices, they can count calls to their
.probe() methods.

This patch:

Remove the assumption that pnp_register_driver() returns the number of devices
claimed.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Adam Belay <ambx1@neo.rr.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>