net/: sparse fixes

bootp.c:44:14: warning: symbol 'dhcp_state' was not declared. Should it be static?
bootp.c:45:15: warning: symbol 'dhcp_leasetime' was not declared. Should it be static?
bootp.c:46:10: warning: symbol 'NetDHCPServerIP' was not declared. Should it be static?
arp.c:30:17: warning: symbol 'NetArpWaitReplyIP' was not declared. Should it be static?
arp.c:37:16: warning: symbol 'NetArpTxPacket' was not declared. Should it be static?
arp.c:38:17: warning: symbol 'NetArpPacketBuf' was not declared. Should it be static?
atheros.c:33:19: warning: symbol 'AR8021_driver' was not declared. Should it be static?
net.c:183:7: warning: symbol 'PktBuf' was not declared. Should it be static?
net.c:159:21: warning: symbol 'net_state' was not declared. Should it be static?
ping.c:73:6: warning: symbol 'ping_start' was not declared. Should it be static?
ping.c:82:13: warning: symbol 'ping_receive' was not declared. Should it be static?
tftp.c:53:7: warning: symbol 'TftpRRQTimeoutMSecs' was not declared. Should it be static?
tftp.c:54:5: warning: symbol 'TftpRRQTimeoutCountMax' was not declared. Should it be static?
eth.c:125:19: warning: symbol 'eth_current' was not declared. Should it be static?

Note: in the ping.c fix, commit a36b12f95a29647a06b5459198684fc142482020
"net: Move PING out of net.c" mistakenly carried the ifdef CMD_PING
clause from when it was necessary to avoid warnings when it was embedded
in net.c.

Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
diff --git a/include/net.h b/include/net.h
index 3539336..970d4d1 100644
--- a/include/net.h
+++ b/include/net.h
@@ -102,12 +102,13 @@
 extern int eth_unregister(struct eth_device *dev);/* Remove network device */
 extern void eth_try_another(int first_restart);	/* Change the device */
 extern void eth_set_current(void);		/* set nterface to ethcur var */
+
 /* get the current device MAC */
+extern struct eth_device *eth_current;
+
 static inline __attribute__((always_inline))
 struct eth_device *eth_get_dev(void)
 {
-	extern struct eth_device *eth_current;
-
 	return eth_current;
 }
 extern struct eth_device *eth_get_dev_by_name(const char *devname);
@@ -517,10 +518,10 @@
 	NETLOOP_SUCCESS,
 	NETLOOP_FAIL
 };
+extern enum net_loop_state net_state;
+
 static inline void net_set_state(enum net_loop_state state)
 {
-	extern enum net_loop_state net_state;
-
 	debug_cond(DEBUG_INT_STATE, "--- NetState set to %d\n", state);
 	net_state = state;
 }