This moves the functions into static const instead of having
funcs and data in the same struct.

It leaves the power callback alone, as it is used in a different
manner.

v2: leave power callback alone (Jani)
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201130210945.31850-1-airlied@gmail.com