drivers: staging: netlogic.h: removed WARNING: extern prototypes should be avoided in .h files

removed checpatch warning : WARNING: extern prototypes should be avoided in .h files
Signed-off-by: Avinash Kumar <avi.kp.137@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/netlogic/xlr_net.h

@@ -1096,4 +1096,4 @@ struct xlr_net_priv {
 	u64 *class_3_spill;
 };
 
-extern void xlr_set_gmac_speed(struct xlr_net_priv *priv);
+void xlr_set_gmac_speed(struct xlr_net_priv *priv);