common: Drop net.h from common header

Move this header out of the common header. Network support is used in
quite a few places but it still does not warrant blanket inclusion.

Note that this net.h header itself has quite a lot in it. It could be
split into the driver-mode support, functions, structures, checksumming,
etc.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/logicpd/am3517evm/am3517evm.c b/board/logicpd/am3517evm/am3517evm.c
index 18f3c3f..6ed3a9b 100644
--- a/board/logicpd/am3517evm/am3517evm.c
+++ b/board/logicpd/am3517evm/am3517evm.c
@@ -12,6 +12,7 @@
 
 #include <common.h>
 #include <dm.h>
+#include <net.h>
 #include <ns16550.h>
 #include <serial.h>
 #include <asm/io.h>
diff --git a/board/logicpd/omap3som/omap3logic.c b/board/logicpd/omap3som/omap3logic.c
index 21d8a21..5c178a2 100644
--- a/board/logicpd/omap3som/omap3logic.c
+++ b/board/logicpd/omap3som/omap3logic.c
@@ -13,6 +13,7 @@
 #include <common.h>
 #include <dm.h>
 #include <init.h>
+#include <net.h>
 #include <ns16550.h>
 #include <netdev.h>
 #include <flash.h>
diff --git a/board/logicpd/zoom1/zoom1.c b/board/logicpd/zoom1/zoom1.c
index 6bfa417..7438d37 100644
--- a/board/logicpd/zoom1/zoom1.c
+++ b/board/logicpd/zoom1/zoom1.c
@@ -16,6 +16,7 @@
 #include <common.h>
 #include <dm.h>
 #include <env.h>
+#include <net.h>
 #include <ns16550.h>
 #include <netdev.h>
 #include <twl4030.h>