can: flexcan: flexcan_clks_enable(): add missing variable initialization

This patch adds the missing initialization of the "err" variable in
the flexcan_clks_enable() function.

Fixes: d9cead75 ("can: flexcan: add mcf5441x support")
Link: https://lore.kernel.org/r/20210728075428.1493568-1-mkl@pengutronix.deReported-by: kernel test robot <lkp@intel.com>
Cc: Angelo Dureghello <angelo@kernel-space.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/flexcan.c

@@ -649,7 +649,7 @@ static inline void flexcan_error_irq_disable(const struct flexcan_priv *priv)
 
 static int flexcan_clks_enable(const struct flexcan_priv *priv)
 {
-	int err;
+	int err = 0;
 
 	if (priv->clk_ipg) {
 		err = clk_prepare_enable(priv->clk_ipg);