pinctrl-msm: Add SPI8 pin definitions

Add pin, group and function definitions for SPI#8
controller.

Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
Acked-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>