gpio: Pass mask and size with the init_valid_mask()

It is more helpful for drivers to have the affected fields
directly available when we use the callback to set up the
valid mask. Change this and switch over the only user
(MSM) to use the passed parameters. If we do this we can
also move the mask out of publicly visible struct fields.

Cc: Stephen Boyd <swboyd@chromium.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20190819084904.30027-1-linus.walleij@linaro.or


Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>