USB: Don't let usb-storage steal Blackberry Pearl

The Blackberry Pearl can run in two modes; a usb-storage only mode
and a mode that allows access via mass storage and to its database.
The berry_charge module will set the device to dual mode and thus we
should ignore its native mode if that module is built

Signed-off-by: Jeremy Katz <katzj@redhat.com>
Signed-off-by: Phil Dibowitz <phil@ipom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>