If for example there are still devices configured on the bus
spi_bus_free() will report that with ESP_ERR_INVALID_STATE, but not
before it frees all other things like IO and DMA. This means that
after the function exits any other task that is still running and
using those devices will all of a sudden stop working (and probably
crash the device).
This commit prevents that situation by making the function return
early so it can be called again safely later when all devices have
been removed.
Closes https://github.com/espressif/esp-idf/pull/13856
Common spi functionality for sharing the SPI bus between modules is moved from esp_driver_spi to
a more fitting location in esp_hw_support (shared HW resource control).
This also allows us to decouple the spi_flash driver from esp_driver_spi, removing
esp_driver_spi and esp_ringbuf from G1 builds.
