linker/*: add section to store module's structures

This will enable us to not use a static
global table like the one in sm_io_mod_dispatch.c.
We will be able to remove this file completely.

linker/bpm-sw.ld

+SECTIONS
+{
+    .smio_mod_dispatch : ALIGN(4)
+    {
+        _smio_mod_dispatch = .;
+        KEEP(*(.smio_mod_dispatch))
+        _esmio_mod_dispatch = .;
+    }
+}
+INSERT AFTER .rodata;