pinctrl: record a pin owner, not mux function, when requesting pins

When pins are requested/acquired/got, some device becomes the owner of
their mux setting. At this point, it isn't certain which mux function
will be selected for the pin, since this may vary between each of the
device's states in the pinctrl mapping table. As such, we should record
the owning device, not what we think the initial mux setting will be,
when requesting pins.

This doesn't make a lot of difference right now since pinctrl_get gets
only one single device/state combination, but this will make a difference
when pinctrl_get gets all states, and pinctrl_select_state can switch
between states.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>