The commit

    commit 5e33577
    Author: Sascha Hauer <s.hauer@pengutronix.de>
    Date:   Tue Mar 29 10:06:46 2016 +0200

        imd: use struct imd_header * as argument

introduces additional imd type checks like this

    if (!imd_is_string(imd->type))
           return NULL;

These checks work incorrectly on any big-endian machine
because the imd->type field needs addition conversion
to little-endian byteorder before use.

Here is the imd command output on big-endian qemu-malta:

    barebox:/ imd /dev/nor0.barebox
    release: <NULL>
    build: <NULL>

This patch fixes the problem by adding necessary conversion
via imd_read_type().

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>