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

1. Add NUC980 Chili board supporting.
2. Correct NuMicro.h including.
3. Implement rt_hw_us_delay system call function.
4. Move board.c to drv_common.c for M480 and M2354 series.

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

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.

2. Fix spi/qspi/uspi TX/RX PDMA trigger issue.
3. Drain RX FIFO to remove remain FEF frames in FIFO.
4. Implement RT_DEVICE_CTRL_CLOSE in uart/uuart/scuart driver.

Fix rtt port issues.