gpio: fix memory and reference leaks in gpiochip_add error path

gpio: fix memory and reference leaks in gpiochip_add error path

commit 5539b3c938d64a60cb1fc442ac3ce9263d52de0c upstream.

Memory allocated and references taken by of_gpiochip_add and
acpi_gpiochip_add were never released on errors in gpiochip_add (e.g.
failure to find free gpio range).

Fixes: 391c970c0dd1 ("of/gpio: add default of_xlate function if device
has a node pointer")
Fixes: 664e3e5ac64c ("gpio / ACPI: register to ACPI events
automatically")

Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
[bwh: Backported to 3.2:
 - Move call to of_gpiochip_add() into conditional section rather
   than rearranging gotos and labels which are in different places
   here
 - There's no ACPI support]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>