spi/pl022: support runtime PM

Insert notifiers for the runtime PM API. With this the runtime
PM layer kicks in to action where used.

Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Reviewed-by: Virupax Sadashivpetimath <virupax.sadashivpetimath@stericsson.com>
Reviewed-by: Jonas Aberg <jonas.aberg@stericsson.com>
Reviewed-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
[Rebased to Linux 3.0-rc3, edit description]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>