spi: remove unused header file <linux/platform_data/spi-clps711x.h>

spi: remove unused header file <linux/platform_data/spi-clps711x.h>

Commit 6acaadc852f1 ("spi: clps711x: Driver refactor") removed the only use
of <linux/platform_data/spi-clps711x.h>, but left the header file behind.
This file is unused, delete it.

Cc: Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20211102220203.940290-9-corbet@lwn.net
Signed-off-by: Mark Brown <broonie@kernel.org>