gpio: dwapb: Use resource managed GPIO-chip add data method

Since the resource managed version of gpiochip_add_data() will handle the
GPIO-chip data automated cleanup we can freely remove the DW APB GPIO
driver code responsible for that. After doing so the DW APB GPIO driver
removal callback can be also fully discarded since there is nothing left
to be done for it. All the cleanups are now performed by means of the
device managed framework.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200730152808.2955-11-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>