driver core: fix driver_match_device

This patch fixes a bug introduced in commit
49b420a1.

If a instance of bus_type doesn't have  .match method,
all .probe of drivers in the bus should be called, or else
the .probe have not a chance to be called.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reported-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>