[ACPI] fix HP nx8220 boot hang regression

[ACPI] fix HP nx8220 boot hang regression

This patch reverts the acpi_bus_find_driver() return value check
that came in via the PCI tree via 3fb02738b0fd36f47710a2bf207129efd2f5daa2

        [PATCH] acpi bridge hotadd: Allow ACPI .add and .start
	operations to be done independently

This particular change broke booting of some HP/Compaq laptops unless
acpi=noirq is used.

http://bugzilla.kernel.org/show_bug.cgi?id=5221
https://bugzilla.novell.com/show_bug.cgi?id=116763

Signed-off-by: Thomas Renninger <trenn@suse.de>
Cc: Rajesh Shah <rajesh.shah@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>