drivers/spi: Cleanup the Kconfig files

Split QMSI relevant part into its own file. Some config where using
prompt, some not: normalizing it by removing the prompt keyword where
relevant.

Reducing the file by using if/endif when relevant.

However, it still not fully clean default: cfg and default baudrate
should disappear. There is no default configuration to apply as long
as the controller is not configured to run from any part using spi API.

Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>