gpio: em: use the managed version of gpiochip_add_data()

Use the managed variant of gpiochip_add_data() and remove the call to
gpiochip_remove().

Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>