1. Add 980 drv_usbd.
2. EMAC - move MDC CLK divider before EMAC initialization.
3. Correct NUC980 and M480 CAN RX_MSG_ID_INDEX definition.
4. add USBD cdc demo - vcom_echo.
5. mnt - add mount_table definition.

1. Fix porting driver.
2. Add NAU8822 audio codec driver.
3. Add NUC980 I2S porting driver.

1. Make up sources and bugfix.
2. Add nu_gpio_pin_get.
3. Add PM operator in USB host driver.
4. Support NUC980 stage 1 and add nk-980iot board.