fbdev: mmp: fix value check in mmphw_probe()

in mmphw_probe(), check the return value of clk_prepare_enable()
and return the error code if clk_prepare_enable() returns an
unexpected value.

Fixes: d63028c3 ("video: mmp display controller support")
Signed-off-by: Yuanjun Gong <ruc_gongyuanjun@163.com>
Signed-off-by: Helge Deller <deller@gmx.de>

drivers/video/fbdev/mmp/hw/mmp_ctrl.c

@@ -519,7 +519,9 @@ static int mmphw_probe(struct platform_device *pdev)
 			      "unable to get clk %s\n", mi->clk_name);
 		goto failed;
 	}
-	clk_prepare_enable(ctrl->clk);
+	ret = clk_prepare_enable(ctrl->clk);
+	if (ret)
+		goto failed;
 
 	/* init global regs */
 	ctrl_set_default(ctrl);