embryo: change the log catagory of printf in embryo

If the catagory is DBG, we should rebuild efl to print the message
by using printf in edc. So change it to use it more convenient.

@fix

src/lib/embryo/embryo_str.c

@@ -445,7 +445,7 @@ _embryo_str_printf(Embryo_Program *ep, Embryo_Cell *params)
 
    _str_snprintf(ep, s1, s2, max_len, pnum, &params[2]);
 
-   DBG("%s", s2);
+   INF("%s", s2);
 
    return o;
 }