staging: rtl8188eu: print OUI with %*ph

There is no need to pass each byte as a parameter when printing values in hex
format. We rather use %*ph specifier for that.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>