RDMA/nes: replace custom print_hex_dump()

There is no need to duplicate a lot of code that is in the kernel library for ages.
Replace duplicating code by calling to print_hex_dump() directly.

Note that output is slightly changed:
- hex and ascii parts have just two spaces delimeter
- there is no delimeter for ascii portions
- file and line removed from prefix (they were redundant anyway since previous
  output shows same closer enough)

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Tatyana Nikolova <tatyana.e.nikolova@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>