The 'ubi_io_read_vid_hdr()' and 'ubi_io_read_ec_hdr()' function
have the 'verbose' argument which controls whether they should
print a warning if the VID/EC header was not found or was corrupted.
Some callers require the headers to be OK, and pass 1. Some allow
a corrupted/not present header, and pass 0.
if (UBI_IO_DEBUG)
verbose = 1;
And UBI_IO_DEBUG is 1 if CONFIG_MTD_UBI_DEBUG_MSG_BLD is true. So in
this case the warning is printed all the time. This confuses people.
Thus, do not print the messages as warnings if UBI_IO_DEBUG is true,
but print them as debugging messages instead.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>