Add STM32F7 SPI support

Merge series from Ben Wolsieffer <ben.wolsieffer@hefring.com>:

This series adds support for SPI on STM32F7 processors. The STM32F7 SPI
peripheral is nearly identical to the STM32F4, with the only significant
differences being that it supports a wider range of word sizes, and the
addition of 32-bit transmit and receive FIFOs.

v2:
  - Add missing commit body

Ben Wolsieffer (5):
  spi: stm32: rename stm32f4_* to stm32fx_*
  spi: stm32: use callbacks for read_rx and write_tx
  dt-bindings: spi: add stm32f7-spi compatible
  spi: stm32: add STM32F7 support
  ARM: dts: stm32: add SPI support on STM32F746

 .../devicetree/bindings/spi/st,stm32-spi.yaml |   1 +
 arch/arm/boot/dts/st/stm32f746.dtsi           |  60 +++
 drivers/spi/spi-stm32.c                       | 455 ++++++++++++------
 3 files changed, 367 insertions(+), 149 deletions(-)

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2.42.0