UART console selection
This change adds a set of menuconfig options to set custom UART#, baud rate, and pins, for console output.
Ref. TW8146
Also includes the following changes:
- `uart_tx_wait_idle`: fix issue with last character not transmitted. ROM function `uart_tx_wait_idle` may have a bug which causes the function to return before the final character is fully transmitted. This replaces `uart_tx_wait_idle` declaration with a static inline definition which fixes the issue. Also replaces the use of `uart_tx_flush` with `uart_tx_wait_idle` in `esp_restart`, to remove garbage in console output on restart.
- `rtc_printf` is temporary replaced with a no-op, pending a new release of librtc.a. Current release assumes that UART0 is used for output,
and switches UART0 baud rate while doing frequency changes and printing some log output. This doesn’t work if a different UART is used for output.
- disable boot watchdog only after starting the main task. Boot watchdogs were disabled very early in startup code. It was possible to introduce an infinite loop anywhere in the many functions called from startup code, and this would not be detected by interrupt watchdog and task watchdog. This change postpones disabling of boot watchdogs to the point when the scheduler is running. Also replaces register expressed using integer address with a name. This change is not directly related to the previous ones, but was found while debugging UART selection features.
See merge request !288
505282bab1