mISDN: hfcmulti: use __iomem address space modifier

Impact: make use of the __iomem address space modifier, and change u_char *,
u_short * and u_int * to void *

Fix more than 30 sparse warnings of this or similar type:

  drivers/isdn/hardware/mISDN/hfcmulti.c:261:31: warning: incorrect type in argument 2 (different address spaces)
  drivers/isdn/hardware/mISDN/hfcmulti.c:261:31:    got unsigned char [usertype] *
  drivers/isdn/hardware/mISDN/hfcmulti.c:261:31:    expected void volatile [noderef] <asn:2>*addr

Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Acked-by: Karsten Keil <kkeil@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>