isdn: hisax: Fix misuse of %x in config.c

Pointers should be printed with %p or %px rather than
cast to (u_long) type and printed with %lX.
As the function seems to be for debug purpose.
Change %lX to %px to print the pointer value.

Signed-off-by: Fuqian Huang <huangfq.daxian@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>