mesa: set _NEW_BUFFERS when updating texture bound to current buffers

mesa: set _NEW_BUFFERS when updating texture bound to current buffers

When a glTexImage call updates the parameters of a currently bound
framebuffer, we might miss out on revalidating whether it is complete.
Make sure to set _NEW_BUFFERS which will trigger the revalidation in
that case.

Also while we're at it, fix the fb parameter passed in to the eventual
RenderTexture call.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94148
Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Cc: "11.2 12.0" <mesa-stable@lists.freedesktop.org>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Tested-by: Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>