spi: Add resets to the PL022 bindings

Some PL022 implementations provide a reset line to the silicon
IP block, add a device tree property for this.

Cc: devicetree@vger.kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20211120011715.2630873-1-linus.walleij@linaro.org


Signed-off-by: Mark Brown <broonie@kernel.org>