fpga: socfpga-a10: disable clk on error in socfpga_a10_fpga_probe()

If fpga_mgr_register() fails, a clock is left undisabled.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Reviewed-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/fpga/socfpga-a10.c

@@ -519,8 +519,14 @@ static int socfpga_a10_fpga_probe(struct platform_device *pdev)
 		return -EBUSY;
 	}
 
-	return fpga_mgr_register(dev, "SoCFPGA Arria10 FPGA Manager",
+	ret = fpga_mgr_register(dev, "SoCFPGA Arria10 FPGA Manager",
 				 &socfpga_a10_fpga_mgr_ops, priv);
+	if (ret) {
+		clk_disable_unprepare(priv->clk);
+		return ret;
+	}
+
+	return 0;
 }
 
 static int socfpga_a10_fpga_remove(struct platform_device *pdev)