Fix some problems with the bin2char utility

Fix some problems with the bin2char utility

Don't hardcode the type for the array, just output the array initializer
so the includer can choose the type and storage class, zero-terminate at
will and so on.

Change-Id: I6d5e0710eaaba0a218b3eb32f6569177356f4462
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/2176
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>