drm: zte: do not enable clock auto-gating by default

Some VOU modules do not work well with clock auto-gating.  For example,
VGA I2C bus will fail to read EDID data from monitor.  Let's not enable
this feature by default, and leave it to the possible future low-power
optimization.
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
Reviewed-by: NSean Paul <seanpaul@chromium.org>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1491490870-6330-2-git-send-email-shawnguo@kernel.org

drivers/gpu/drm/zte/zx_vou.c

@@ -705,9 +705,6 @@ static void vou_hw_init(struct zx_vou_hw *vou)
 	/* Release reset for all VOU modules */
 	zx_writel(vou->vouctl + VOU_SOFT_RST, ~0);
 
-	/* Enable clock auto-gating for all VOU modules */
-	zx_writel(vou->vouctl + VOU_CLK_REQEN, ~0);
-
 	/* Enable all VOU module clocks */
 	zx_writel(vou->vouctl + VOU_CLK_EN, ~0);