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/drivers/crypto/ace_sha.c b/drivers/crypto/ace_sha.c
index 3461105..b5321ed 100644
--- a/drivers/crypto/ace_sha.c
+++ b/drivers/crypto/ace_sha.c
@@ -5,6 +5,7 @@
  */
 #include <common.h>
 #include "ace_sha.h"
+#include <rand.h>
 
 #ifdef CONFIG_SHA_HW_ACCEL
 #include <u-boot/sha256.h>