spi: stm32: introduce compatible data cfg

Prepare support for STM32F4 spi variant by introducing compatible
configuration data.
Move STM32H7 specific stuff to compatible data structure:
 - registers & bit fields
 - routines to control driver
 - baud rate divisor definitions
 - fifo availability
 - split IRQ functions to parts to be called when the IRQ occurs
   and for threaded interrupt what helps to provide less discontinuous
   mode for drivers without FIFO.
Signed-off-by: NCezary Gapinski <cezary.gapinski@gmail.com>
Signed-off-by: NMark Brown <broonie@kernel.org>