pinctrl: berlin: comment the spi functions

Add comments for the SPI functions, to distinguish CLK, SDI, SDO and
C{0,1,2,3}n.

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
3 files changed