v3dv: Fix assert.

v3dv: Fix assert.

Fix defect reported by Coverity Scan.

Side effect in assertion (ASSERT_SIDE_EFFECT)
assignment_where_comparison_intended: Assignment job->ez_state =
VC5_EZ_DISABLED has a side effect. This code will work differently in a
non-debug build.

Fixes: cec2ed7c80f ("v3dv: fix disabling Early Z for the whole frame")
Signed-off-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8666>