musb: Update usb-compat to work with struct usb_device without a parent ptr

[u-boot] / configs / woodburn_sd_defconfig

CONFIG_ARM=y
CONFIG_TARGET_WOODBURN_SD=y
CONFIG_SPL=y
CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/woodburn/imximage.cfg"
# CONFIG_CMD_SETEXPR is not set