6lowpan: move IPHC functionality defines

This patch removes the IPHC related defines for doing bit manipulation
from global 6lowpan header to the iphc file which should the only one
implementation which use these defines.

Also move next header compression defines to their nhc implementation.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/ieee802154/6lowpan/tx.c

@@ -14,6 +14,9 @@
 
 #include "6lowpan_i.h"
 
+#define LOWPAN_FRAG1_HEAD_SIZE	0x4
+#define LOWPAN_FRAGN_HEAD_SIZE	0x5
+
 /* don't save pan id, it's intra pan */
 struct lowpan_addr {
 	u8 mode;