media: drxk: Use %*ph for printing hexdump of a small buffer

The kernel already has a helper to print a hexdump of a small
buffer via pointer extension. Use that instead of open coded
variant.

In long term it helps to kill pr_cont() or at least narrow down
its use.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>