This commit ensures that RTC data is properly allocated in the RTC
segment in the linker. This fixes the reported problem about using
the legacy bootloader and RTC.
ESP32 SoC use a static allocated array as idle stack. To fit
the existed idle stack allocation, make idle stack allocated
from ebss for the whole esp32 series.
Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
