Update saibcm-modules and saibcm-modules-dnx due to kernel changes

Add an include in saibcm-modules and saibcm-modules-dnx that are now
needed due to Mellanox kernel patches.

Signed-off-by: Saikrishna Arcot <sarcot@microsoft.com>

platform/broadcom/saibcm-modules/sdklt/linux/knet/ngknet_main.c

@@ -66,6 +66,7 @@
 #include <linux/uaccess.h>
 #include <linux/module.h>
 #include <linux/netdevice.h>
+#include <linux/ethtool.h>
 #include <linux/etherdevice.h>
 #include <linux/skbuff.h>
 #include <linux/if.h>