In case WiFi/BT stack has been enabled but wasn’t disabled, some RTC
bits may be left enabled, causing increased current consumption.
This change returns some of the bits back to their default values.
Deep sleep stub may call ets_update_cpu_frequency, which has been moved from ROM to IRAM.
Restore the ROM version in the linker script, call it ets_update_cpu_frequency_rom, use it in the deep sleep stub.
This change allows setting pin configuration for EXT1 wakeup depending on the state of RTC_PERIPH power domain:
- if peripherals are enabled (due to another wakeup mode, or due to esp_deep_sleep_pd_config call), we can keep internal pullups/pulldowns enabled
- if peripherals are disabled, pullups and pulldowns need to be disabled as well
Also add comments about the purpose of registers being configured.
