1. Import M031 porting.
2. Support numaker-m032ki BSP.

(1) Support NK-N9H30 board.
(2) Change Mutex's flag to RT_IPC_FLAG_PRIO from RT_IPC_FLAG_FIFO.

1. Add NuMaker-M2354 BSP.
2. Fix SLCD library and modify its demo.

1. NUC980 platform: USBH, INPUTCAPTURE, SPINAND.
2. Correct enter-quad-mode routine in board_dec.c.
3. Use RT_ASSERT to catch system-call-exceptions.

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.

Fix rtt port issues.