wimax/i2400m: move I2400M_MAX_MTU enum from netdev.c to i2400m.h

This patch moves I2400M_MAX_MTU enum defined in netdev.c to i2400m.h.
Follow up changes will make use of this value in other location,
thus requiring it to be moved to a global header file i2400m.h.
Signed-off-by: Prasanna S. Panchamukhi <prasannax.s.panchamukhi@intel.com>
Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>

drivers/net/wimax/i2400m/i2400m.h

@@ -160,6 +160,16 @@
 #include <linux/wimax/i2400m.h>
 #include <asm/byteorder.h>
 
+enum {
+/* netdev interface */
+	/*
+	 * Out of NWG spec (R1_v1.2.2), 3.3.3 ASN Bearer Plane MTU Size
+	 *
+	 * The MTU is 1400 or less
+	 */
+	I2400M_MAX_MTU = 1400,
+};
+
 /* Misc constants */
 enum {
 	/* Size of the Boot Mode Command buffer */

drivers/net/wimax/i2400m/netdev.c

@@ -84,12 +84,6 @@
 
 enum {
 /* netdev interface */
-	/*
-	 * Out of NWG spec (R1_v1.2.2), 3.3.3 ASN Bearer Plane MTU Size
-	 *
-	 * The MTU is 1400 or less
-	 */
-	I2400M_MAX_MTU = 1400,
 	/* 20 secs? yep, this is the maximum timeout that the device
 	 * might take to get out of IDLE / negotiate it with the base
 	 * station. We add 1sec for good measure. */