ppc: Fix compile warnings when !CONFIG_OF_LIBFDT

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>

lib_ppc/bootm.c

@@ -224,12 +224,13 @@ static int boot_bd_t_linux(bootm_headers_t *images)
 
 static int boot_body_linux(bootm_headers_t *images)
 {
-	ulong rd_len, bootmap_base = getenv_bootm_low();
-	ulong of_size = images->ft_len;
+	ulong rd_len;
 	struct lmb *lmb = &images->lmb;
 	ulong *initrd_start = &images->initrd_start;
 	ulong *initrd_end = &images->initrd_end;
 #if defined(CONFIG_OF_LIBFDT)
+	ulong bootmap_base = getenv_bootm_low();
+	ulong of_size = images->ft_len;
 	char **of_flat_tree = &images->ft_addr;
 #endif