Use %*ph format to print small buffer as hex string.

Remove newline at the end of the format string as it would be duplicated
by the one supplied as last argument.
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Antonio Cardace <anto.cardace@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>