ieee802154: mcr20a: add missing includes

Without CONFIG_GPIOLIB, some headers are not included implicitly,
leading to a build failure:

drivers/net/ieee802154/mcr20a.c: In function 'mcr20a_probe':
drivers/net/ieee802154/mcr20a.c:1347:13: error: implicit declaration of function 'irq_get_trigger_type'; did you mean 'irq_get_irqchip_state'? [-Werror=implicit-function-declaration]

This includes gpio/consumer.h and irq.h directly rather through the
gpiolib header.

Fixes: 8c6ad9cc ("ieee802154: Add NXP MCR20A IEEE 802.15.4 transceiver driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Xue Liu <liuxuenetmail@gmail.com>
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>