Add source code for sdk_wifi_param_save_protect() and a compile time,
WIFI_PARAM_SAVE, option to skip writing the wifi state to flash. This
avoids wear on the flash and does not appear to be necessary when the
app initializes the state anyway.
Define WIFI_PARAM_SAVE to 0 for the wificfg example.
* The mdns responder has been reworked to lower stack and memory usage. This is
a variation on the upstream code, it use malloc whereas the upstream code uses
pools. The high stack usage of the mdns responder was problem for
esp-open-rtos, so we might have to maintain the differences for now.
* Improved lwip core locking, and lock checking. Upstream improvements, that
need some added support from esp-open-rtos specific code. More core lock is
performed when calling from the esp-open-rtos code now, so a little safer. The
checking is not enforced, but projects might see warning messages and might
want to look into them.
* The esp-open-rtos lwip support has been sync'ed with the new freertos port
included with lwip. There are still some minor differences.
* A few lwip timer bugs have been resolved. This might help resolve some issues.
* Plus it picks up all the other upstream fixes and improvements.
* The default lwip stack has been lowered from 768 words to 480 words,
due to the reduced stack usage by the mdns responder.
Fix sdk_system_rtc_mem_write and sdk_system_rtc_mem_read,
the functions did not use the user-provided offsets to rtc_mem.
Without using offset, rboot's rtcdata access, and its
temp_rom handling were broken.
Add source code for functions touching the struct netif to better support lwip development: sdk_wifi_get_ip_info, sdk_wifi_set_ip_info, sdk_wifi_get_macaddr, sdk_wifi_set_macaddr.
Also code for sdk_wifi_station_get_connect_status.
Also code for wifi_get_sleep_type and set_sleep_type, noting wifi_set_sleep_type returns a bool success flag, and implement wifi_get_sleep_type using sdk_pm_get_sleep_type.
Also comment the point at which the bus clock that drives the uart changes on startup and comment out the change in the uart divisor. This at least allows a consistent uart baud rate during a restart if using the rate 115200.
* wifi_set_sleep_type returns a bool success flag.
* wifi_get_sleep_type seemed useless, just returning an argument. Added an implementation using sdk_pm_get_sleep_type.
