cmd: fix mtest on 64 bit systems

* Use 16 digits on 64 bit systems.
* Use 64 bit patterns on 64 bit systems.
* Expect the sign bit in bit 63 on 64 bit systems.
* Adjust the formatting of a constant.
* Always print result on new line

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Stefan Roese <sr@denx.de>
1 file changed