gpio: Pass a flag to gpiochip_request_own_desc()

gpio: Pass a flag to gpiochip_request_own_desc()

Before things go out of hand, make it possible to pass
flags when requesting "own" descriptors from a gpio_chip.
This is necessary if the chip wants to request a GPIO with
active low semantics, for example.

Cc: Janusz Krzysztofik <[email protected]>
Cc: Thomas Petazzoni <[email protected]>
Cc: Jason Cooper <[email protected]>
Cc: Jiri Kosina <[email protected]>
Cc: Roger Quadros <[email protected]>
Reviewed-by: Gregory CLEMENT <[email protected]>
Signed-off-by: Linus Walleij <[email protected]>