drivers: i2s_mcux_sai: Clean up top of file

Put DT_DRV_COMPAT at top of file by custom

Consolidate logging macros

Clean up checks and use build assert

Remove header file which was not necessary

Remove unnecessary forward declarations

Fix the type of the stream state to be more precise, it is used as the
enum i2s_state type. This requires handling all the enum cases in switch
statements

Signed-off-by: Declan Snyder <declan.snyder@nxp.com>