Dual/Quadmode spidev

[mfield4]

This change adds the ability to explicitly request Single, Dual, or Quad SPI modes via a new operation_mode option in the SPI transport. It includes the necessary logic to map these modes to the appropriate spidev bit counts and SPI NOR opcodes.

1. New libhoth_spi_mode Enum: Added LIBHOTH_SPI_MODE_SINGLE, LIBHOTH_SPI_MODE_DUAL, and LIBHOTH_SPI_MODE_QUAD.
2. Enhanced Initialization: libhoth_spi_open now configures the SPI device mode using SPI_IOC_WR_MODE32 and verifies the setting.
3. Sticky Mode Prevention: The original SPI mode is now backed up during initialization and restored in libhoth_spi_close to ensure that mode settings do not persist across different processes.
4. Opcodes and Bitmasks; Added helper functions to correctly set the opcodes and *_nbits fields based on the selected mode.