Test environment: i.MX8ULP EVK, SDK2.16
Some customer want to use LPUART2 in DSP domain on M33. This patch is based on lpuart_polling.
Hardware test point:
If you send data from uart2, you will get such log from M33 console:
reg = d2000000, 94000000
LPUART_WriteBlocking
get readbuf = 73
get readbuf = 73
