To make compositive usb device string more reansonable, not all devices
just show same "RTT Composite Device" on windows device manager.

add a interface rt_usbd_device_set_interface_string to set respective
interface string.
Signed-off-by: NDillon Min <dillon.minfei@gmail.com>
v1 -> v2: remove all tabs to space, to match rt-thread coding style

1. delete '#include <rtservice.h>', because rtthread.h had include rtservice.h;
2. delete '#include <rtthread.h>', because rtdevice.h had include rtthread.h.

1. Limit >4 USB ports hubs.
2. Double free intf.
3. dname buffer size is too small.
4. Reset child pointer after detaching instance.

Fix miss-break in HWTIMER_CTRL_INFO_GET case.

mstorage.c: fix the issue that _read_capacity() returns the wrong last valid address of storage medium

Signed-off-by: NCliff Chen <cliff.chen@rock-chips.com>

rt_kprintf("alloc memery failed\n"); -> rt_kprintf("alloc memory failed\n");