spi: Fix SPI_CS_HIGH setting when using native and GPIO CS

When improving the CS GPIO support at core level, the SPI_CS_HIGH
has been enabled for all the CS lines used for a given SPI controller.

However, the SPI framework allows to have on the same controller native
CS and GPIO CS. The native CS may not support the SPI_CS_HIGH, so they
should not be setup automatically.

With this patch the setting is done only for the CS that will use a
GPIO as CS

Fixes: f3186dd8

 ("spi: Optionally use GPIO descriptors for CS GPIOs")
Cc: <stable@vger.kernel.org>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Link: https://lore.kernel.org/r/20191018152929.3287-1-gregory.clement@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>