Register _childdetached methods with drivers that attach children.
Wait to set child references to NULL there, instead of doing that
in the detach method.
Replace many uses of USB_DECLARE_DRIVER() with CFATTACH_DECL2().
PR/37692 from Yojiro UO
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uhmodem: device driver for huawei 3G wireless modem
* what it is?
A device driver for huawei 3G wireless modem, E220 and its valiations.
The devices are very simuler to ubsa device, but they need special care
to use as modem device.
This patch introduce "uhmodem (USB Huawei modem)" for the devices.
A uhmodem device has two com devices and one USB mass strage device.
The driver enable to use all of them.
* dmesg:
uhmodem0 at uhub0 port 1 configuration 1 interface 0
uhmodem0: HUAWEI Technologies HUAWEI Mobile, rev 1.10/0.00, addr 2
uhmodem0: mass storage only mode, reattach to enable modem
uhmodem0: at uhub0 port 1 (addr 2) disconnected
uhmodem0 detached
uhmodem0 at uhub0 port 1 configuration 1 interface 0
uhmodem0: HUAWEI Technologies HUAWEI Mobile, rev 1.10/0.00, addr 2
ucom0 at uhmodem0 portno 0: modem
ucom1 at uhmodem0 portno 1: monitor
umass0 at uhub0 port 1 configuration 1 interface 2
umass0: HUAWEI Technologies HUAWEI Mobile, rev 1.10/0.00, addr 2
umass0: using SCSI over Bulk-Only
scsibus0 at umass0: 2 targets, 1 lun per target
cd0 at scsibus0 target 0 lun 0: <HUAWEI, Mass Storage, 2.31> cdrom removable
cube