drivers: clk: keystone: Fix parameter judgment in _of_pll_clk_init()

The function clk_register_pll() may return NULL or an ERR_PTR. Don't
treat an ERR_PTR as valid.
Signed-off-by: Minjie Du <duminjie@vivo.com>
Link: https://lore.kernel.org/r/20230712102246.10348-1-duminjie@vivo.com
Fixes: b9e0d40c ("clk: keystone: add Keystone PLL clock driver")
[sboyd@kernel.org: Reword commit text]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/keystone/pll.c

@@ -209,7 +209,7 @@ static void __init _of_pll_clk_init(struct device_node *node, bool pllctrl)
 	}
 
 	clk = clk_register_pll(NULL, node->name, parent_name, pll_data);
-	if (clk) {
+	if (!IS_ERR_OR_NULL(clk)) {
 		of_clk_add_provider(node, of_clk_src_simple_get, clk);
 		return;
 	}