cmd_flash.c: fix fix compile error for boards with DataFlash

Commit 5669ed45 ("cmd_flash.c: fix warning: unused variable
'addr_first'/'addr_last'") changed the #ifdef logic areound the
declaration of these variables and missed a combination of settings
of HAS_DATAFLASH with SYS_NO_FLASH; this patch fixes this.

Also spotted by Alessandro Rubini <rubini@gnudd.com>
Signed-off-by: NWolfgang Denk <wd@denx.de>

common/cmd_flash.c

@@ -467,8 +467,10 @@ int do_protect (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 	flash_info_t *info;
 	ulong bank;
 	int i, n, sect_first, sect_last;
-	ulong addr_first, addr_last;
 #endif /* CONFIG_SYS_NO_FLASH */
+#if !defined(CONFIG_SYS_NO_FLASH) || defined(CONFIG_HAS_DATAFLASH)
+	ulong addr_first, addr_last;
+#endif
 #if defined(CONFIG_CMD_JFFS2) && defined(CONFIG_CMD_MTDPARTS)
 	struct mtd_device *dev;
 	struct part_info *part;