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/lib/efi_selftest/efi_selftest_block_device.c b/lib/efi_selftest/efi_selftest_block_device.c
index d98a854..5eb297d 100644
--- a/lib/efi_selftest/efi_selftest_block_device.c
+++ b/lib/efi_selftest/efi_selftest_block_device.c
@@ -15,6 +15,7 @@
 
 #include <efi_selftest.h>
 #include "efi_selftest_disk_image.h"
+#include <asm/cache.h>
 
 /* Block size of compressed disk image */
 #define COMPRESSED_DISK_IMAGE_BLOCK_SIZE 8