support line mode 1-2-4-8 depend on targets.
fix sct mode dma descriptor counter compute issue.
add conf_bits_len setting API to control interval time.
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.