l2: l2_patch_main should not be static

Without understanding what is going on,
a pattern from l2_fwd.c is applied to l2_patch.c file.

Type: fix
Fixes: d770cfc962
Ticket: VPP-1799

Change-Id: Ia97d448f9d1846549f57ea69044ae15fa39bb942
Signed-off-by: Vratko Polak <vrpolak@cisco.com>
(cherry picked from commit 3be9351e5e)

src/vnet/l2/l2_patch.c

@@ -49,7 +49,11 @@ format_l2_patch_trace (u8 * s, va_list * args)
   return s;
 }
 
-static l2_patch_main_t l2_patch_main;
+#ifndef CLIB_MARCH_VARIANT
+l2_patch_main_t l2_patch_main;
+#else
+extern l2_patch_main_t l2_patch_main;
+#endif
 
 extern vlib_node_registration_t l2_patch_node;