mesa/framebuffer: fix gl_framebuffer.resolve refcnt imbalance

mesa/framebuffer: fix gl_framebuffer.resolve refcnt imbalance

Indeed, "resolve" is not freed at the gl_framebuffer destroy
stage.

For instance, this issue is triggered and detected with
"piglit/bin/fbo-depthstencil clear default_fb -samples=2 -auto"
while setting GALLIUM_REFCNT_LOG=refcnt.log.

Fixes: f5bde99cbdd2 ("gallium: plumb resolve attachments through from frontends -> pipe_framebuffer_state")
Signed-off-by: Patrick Lerda <patrick9876@free.fr>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21663>