As we found that simple ion / drm device detectioin can not cover all the
case. For example on some 3368 platform kernel provide both ion and drm
device. We have better to use allocator chosen in dts.
But later kernel patch from Randy will bring unified dma-fd translation in
kernel then this detection will be removed.
Change-Id: I2746142d1c3d0f36791bacaadb231dc2001a5aa7
Signed-off-by: Herman Chen <herman.chen@rock-chips.com>
