common/cmd_bdinfo.c: fix do_bdinfo() for AVR32

This patch fixes following warning message:

---8<---
cmd_bdinfo.c:458: warning: initialization from incompatible pointer type
--->8---

There was a prototype change in 54841ab5 for
argv[] pointer type to const. This change was not made for AVR32 cause this
code came in later by a merge.

Signed-off-by: Andreas Bießmann <biessmann@corscience.de>

common/cmd_bdinfo.c

@@ -304,7 +304,7 @@ int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 
 #elif defined(CONFIG_AVR32)
 
-int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_bdinfo ( cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	bd_t *bd = gd->bd;