can: flexcan: remove unused header files

This patch removes unused header files from the flexcan driver.
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/flexcan.c

@@ -26,12 +26,8 @@
 #include <linux/can/led.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
-#include <linux/if_arp.h>
-#include <linux/if_ether.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
-#include <linux/kernel.h>
-#include <linux/list.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>