drm/v3d: Flush the MMU before we supply more memory to the binner

We must ensure that the MMU is flushed before we supply more memory to
the binner, otherwise we might end up with invalid MMU accesses by the
GPU.

Fixes: 57692c94 ("drm/v3d: Introduce a new DRM driver for Broadcom V3D V3.x+")
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240923141348.2422499-3-mcanal@igalia.com