Driver improvements (#535)

- New drivers:
  - SD SPI
  - spi_peripheral
  - touch_placeholder
  - display_placeholder
- Devicetree compiler:
  - Implement phandle-arrays
  - Implement device addresses
- Add placeholder drivers to all devices with a SPI display
- SPI driver: add `cs-pins` and set them to high on driver start
- FileSystem: add `file_system_set_owner()` and `file_system_get_owner()`
- File locking is now checking if the related `FileSystem` is part of a shared SPI bus
- Add `device_get_child_count()`
- SDMMC driver: Remove default of `slot` value
- Fix for Crowpanel Basic 3.5" display (add delay to booting)
- Fix for LilyGO T-HMI SD card mounting (delayed mounting by disabling it initially in the dts)

TactilityKernel/source/device.cpp

@@ -328,6 +328,10 @@ void device_for_each_child(Device* device, void* callbackContext, bool(*on_devic
     }
 }
 
+size_t device_get_child_count(Device* device) {
+    return device->internal->children.size();
+}
+
 void device_for_each_of_type(const DeviceType* type, void* callbackContext, bool(*on_device)(Device* device, void* context)) {
     ledger_lock();
     for (auto* device : ledger.devices) {