gralloc: Allow overriding the framebuffer device

On some devices, different outputs use different
framebuffer devices - e.g. on iMX6, /dev/fb0 is
the LVDS display, and /dev/fb1 is the HDMI
output.

Simply opening the first device that exists may
not be what we want - allow overrides on the
bootargs line

Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>
1 file changed