When setting the dst framebuffer width height, it might be silly
to constrain this beyond the dst resource, but at least constrain
it correctly to take account of x/y offsets.
This fixes some uses of this as a fallback for zink with
GTF-GL46.gtf30.GL3Tests.framebuffer_blit.framebuffer_blit_functionality_stencil_blit
Fixes: b4c07a8a87 ("gallium/util: allow scaling blits for stencil-fallback")
Reviewed-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Acked-by: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16069>
(cherry picked from commit dbc264f504)
048813108f