Added ioctl wrappers for simple G2D fill and blit operations

The existing kernel driver from Allwinner for G2D accelerator
is quite bad because ioctls are synchronous and blocking the
caller thread, compromise security (basically it is a backdoor
for copying data in memory between any arbitrary physical
addresses) and have high overhead (each individual fill or
blit operation needs an ioctl). But we need to start with
something, so use this stuff as a placeholder.

The g2d_driver.h header file is taken from linux-sunxi-3.4

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>