mtd: slram: invalid checking of absolute end address

Fixed parsing end absolute address.
Signed-off-by: NJiri Engelthaler <engycz@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

drivers/mtd/devices/slram.c

@@ -240,7 +240,7 @@ static int parse_cmdline(char *devname, char *szstart, char *szlength)
 
 	if (*(szlength) != '+') {
 		devlength = simple_strtoul(szlength, &buffer, 0);
-		devlength = handle_unit(devlength, buffer) - devstart;
+		devlength = handle_unit(devlength, buffer);
 		if (devlength < devstart)
 			goto err_out;