common: mii: Do not allow to exceed max phy limit

Phy can have addresses 0-31. Check this boundary to ensure that user
can't call commands on phy address 32 and more.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

common/cmd_mii.c

@@ -314,6 +314,11 @@ static int do_mii(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 			mask = simple_strtoul(argv[5], NULL, 16);
 	}
 
+	if (addrhi > 31) {
+		printf("Incorrect PHY address. Range should be 0-31\n");
+		return CMD_RET_USAGE;
+	}
+
 	/* use current device */
 	devname = miiphy_get_current_dev();