nv30: Fix max width / height checks in nv30 sifm code

nv30: Fix max width / height checks in nv30 sifm code

The sifm object has a limit of 1024x1024 for its input size and 2048x2048
for its output. The code checking this was trying to be clever resulting
in it seeing a surface of e.g 1024x256 being outside of the input size
limit.

This commit fixes this.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>
Cc: "10.6 11.0" <mesa-stable@lists.freedesktop.org>