etnaviv: Do GC3000 resolve-in-place when possible

etnaviv: Do GC3000 resolve-in-place when possible

If an RS blit is done with source exactly the same as destination, and
the hardware supports this, do an in-place resolve. This only fills in
tiles that have not been rendered to using information from the TS.

This is the same as the blob does and potentially saves significant
bandwidth when doing i.MX6qp scanout using PRE, and when rendering to
textures (though here using sampler TS would be even better).

Signed-off-by: Wladimir J. van der Laan <laanwj@gmail.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>