staging: kpc2000: Use '%llx' for printing 'long long int' type

In order to print a 'long long int' type the 'llx' specifier needs to be
used.

Change it accordingly in order to fix the following build warning:

drivers/staging/kpc2000/kpc2000/core.c:245:4: warning: format '%lx' expects argument of type 'long unsigned int', but argument 4 has type 'long long int' [-Wformat=]

Reported-by: Build bot for Mark Brown <broonie@kernel.org>
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>