gadget: usbled: add USB_REQ_SET_CONFIGURATION

sudo lsusb -vd 1987:0827

Bus 002 Device 035: ID 1987:0827
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0
  bDeviceProtocol         0
  bMaxPacketSize0         8
  idVendor           0x1987
  idProduct          0x0827
  bcdDevice            0.00
  iManufacturer           1 U-Boot
  iProduct                2 usb led gadget
  iSerial                 3 1
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           18
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0
    bmAttributes         0xc0
      Self Powered
    MaxPower                2mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         0 (Defined at Interface level)
      bInterfaceSubClass      0
      bInterfaceProtocol      0
      iInterface              0
Device Status:     0x0009
  Self Powered

dmesg
[89385.816064] usb 2-2: USB disconnect, device number 34
[89387.164033] usb 2-2: new full-speed USB device number 35 using uhci_hcd
[89387.801897] usb 2-2: New USB device found, idVendor=1987, idProduct=0827
[89387.801906] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[89387.801911] usb 2-2: Product: usb led gadget
[89387.801916] usb 2-2: Manufacturer: U-Boot
[89387.801920] usb 2-2: SerialNumber: 1

Signed-off-by: Fudong Bai <fudongbai@gmail.com>
gadget: usbled: add usb_led_switch and disconnect

Signed-off-by: Fudong Bai <fudongbai@gmail.com>
tools: build usbled test app

Signed-off-by: Fudong Bai <fudongbai@gmail.com>
boot_usb: fix build error and report error when download ends

1. build error is caused by link process

2. complaining error is caused the return value not properly handled
usb_bulk_write will return the bytes actuall wrote to the usb device,
but orginal code will return an error when the return value is not zero,
which is not correct.

Signed-off-by: Fudong Bai <fudongbai@gmail.com>
gadget: usbled: changed serial number

Signed-off-by: Fudong Bai <fudongbai@gmail.com>