clk: clk-atlas6: fix return value check in atlas6_clk_init()

In case of error, the function clk_register() returns ERR_PTR()
and never returns NULL. The NULL test in the return value check
should be replaced with IS_ERR().
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Link: https://lore.kernel.org/r/20200713032143.21362-1-vulab@iscas.ac.cnAcked-by: Barry Song <baohua@kernel.org>
Fixes: 7bf21bc8 ("clk: sirf: re-arch to make the codes support both prima2 and atlas6")
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/sirf/clk-atlas6.c

@@ -135,7 +135,7 @@ static void __init atlas6_clk_init(struct device_node *np)
 
 	for (i = pll1; i < maxclk; i++) {
 		atlas6_clks[i] = clk_register(NULL, atlas6_clk_hw_array[i]);
-		BUG_ON(!atlas6_clks[i]);
+		BUG_ON(IS_ERR(atlas6_clks[i]));
 	}
 	clk_register_clkdev(atlas6_clks[cpu], NULL, "cpu");
 	clk_register_clkdev(atlas6_clks[io],  NULL, "io");