There's no need for this to be modifiable. Make it const so that it can
be put into the .rodata section.
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NThierry Reding <treding@nvidia.com>
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDave Airlie <airlied@redhat.com>