[ARM] 5546/1: ARM PL022 SSP/SPI driver v3

This adds a driver for the ARM PL022 PrimeCell SSP/SPI
driver found in the U300 platforms as well as in some
ARM reference hardware, and in a modified version on the
Nomadik board.

Reviewed-by: Alessandro Rubini <rubini-list@gnudd.com>
Reviewed-by: Russell King <linux@arm.linux.org.uk>
Reviewed-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>