ubi-utils: nand2bin had ECC calculation problems

ubi-utils: nand2bin had ECC calculation problems

Fixed a problem when ECC was checked. The correction was not properly
done by subpage. Added more output for the moment to be able to figure
out more potential problems.

Added testcase: bin2nand2bin.sh and biterror inject program inject_biterror.pl

Interface
  o ECC correction disabled by default. Switch to turn it
    explicitly on. The user must specify what he wants to be done.

Signed-off-by: Frank Haverkamp <haver@vnet.ibm.com>