Create gpiomem kernel driver for Allwinner H3

[mstroh76]

bcm2835-gpiomem source
https://github.com/eq-3/RaspberryMatic/blob/master/linux-4.1/drivers/char/broadcom/bcm2835-gpiomem.c

/dev/gpiomem is a Raspberry Pi only driver - there is no such driver for allwinner.