etnaviv: move printing of final shader out of etna_link_shaders(..)

etnaviv: move printing of final shader out of etna_link_shaders(..)

Printing the final shaders in etna_link_shaders(..) can be quite noisy and
does not work when using shader-db. Lets make it possible to stare at the
generaded shader code when using shader-db by moving the etna_dump_shader(..)
call into create_variant(..).

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23396>