boards: lilygo: ttgo_lora32: enable SDHC support

device tree:
enable support for the SDHC controller to use the micro SD card slot

documentation:
- added instructions for SD card and OLED samples
- added links to code samples

defconfig:
added CONFIG_ESP32_USE_UNSUPPORTED_REVISION=y to
ttgo_lora32_esp32_procpu_defconfig

The chip on the board is a ESP32 chip revision 1.
The board will not boot, it displays the following warning at boot:

I (35) boot: chip revision: v1.0
E (38) boot: You are using ESP32 chip revision (1) that is unsupported.
While it may work, it could cause unexpected behavior or issues.
E (50) boot: Proceeding with this ESP32 chip revision is not recommended
unless you fully understand the potential risk and limitations.
E (62) boot: If you choose to continue, please enable the
'CONFIG_ESP32_USE_UNSUPPORTED_REVISION' in your project configuration.
E (73) boot: HW init failed, aborting

In order to prevent a boot loop, CONFIG_ESP32_USE_UNSUPPORTED_REVISION=y
was added to the defconfig.

Signed-off-by: Lothar Felten <lothar.felten@gmail.com>
6 files changed