clk: ti: dra7-atl: Provide error check for incoming parameters in set_rate

Check for valid parameters in check rate. Else, we end up getting
errors.

This occurs as part of the inital clock tree update of child clock
nodes where new_rate could be 0 for non functional clocks.

Fixes: 9ac33b0c (" CLK: TI: Driver for DRA7 ATL (Audio Tracking Logic)")
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>

drivers/clk/ti/clk-dra7-atl.c

@@ -139,9 +139,13 @@ static long atl_clk_round_rate(struct clk_hw *hw, unsigned long rate,
 static int atl_clk_set_rate(struct clk_hw *hw, unsigned long rate,
 			    unsigned long parent_rate)
 {
-	struct dra7_atl_desc *cdesc = to_atl_desc(hw);
+	struct dra7_atl_desc *cdesc;
 	u32 divider;
 
+	if (!hw || !rate)
+		return -EINVAL;
+
+	cdesc = to_atl_desc(hw);
 	divider = ((parent_rate + rate / 2) / rate) - 1;
 	if (divider > DRA7_ATL_DIVIDER_MASK)
 		divider = DRA7_ATL_DIVIDER_MASK;