imxtools: use rand() instead of /dev/random.

On Windows /dev/random does not exist, so trying to open it will fail. Replace
it with rand() which is available on all supported platforms and sufficient.

Fixes mkimxboot not working, as well as Rockbox Utility "crashing" (which is in
fact its error handler calling exit(), thus terminating Rockbox Utility) on
Windows.

Change-Id: Ia164f937f329877e8f80f473f27be8c5df2a0a68
1 file changed