drivers: i2s_cavs: Add bidirectional I2S support

Added bidirectional I2S support for Intel S1000

- Added implementation for I2S receive mode
- Extended driver instances to support 3 I2S ports
- Added DMA channel mappings for upto 4 I2S ports
- Utilized k_msgq to track buffers through the driver
    - Allocate buffers for audio reception in the driver
    - Free buffers after audio transmission in the driver
- Perform buffer reload for DMA after every reception/transmission
- Removed unused Kconfig variables
    - I2S_CAVS_TX_BLOCK_COUNT
    - I2S_CAVS_RX_BLOCK_COUNT

Signed-off-by: Sathish Kuttan <sathish.k.kuttan@intel.com>