drm/etnaviv: relax submit size limits

While all userspace tried to limit commandstreams to 64K in size,
a bug in the Mesa driver lead to command streams of up to 128K
being submitted. Allow those to avoid breaking existing userspace.

Fixes: 6dfa2fab

 ("drm/etnaviv: limit submit sizes")
Cc: stable@vger.kernel.org
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>