spi/clps711x: New SPI master driver

This patch add new driver for CLPS711X SPI master controller.
Due to platform limitations driver supports only 8 bit transfer mode.
Chip select control is handled via GPIO.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>