[PATCH] s390: 32 bit ioctl emulation fixes.

[PATCH] s390: 32 bit ioctl emulation fixes.

From: Martin Schwidefsky <schwidefsky@de.ibm.com>

- audit all 32 bit pointer accesses and make them use compat_ioctl(),
  because of the necessary conversion on s390
- introduce ULONG_IOCTL() which is used instead of COMPATIBLE_IOCTL()
  for all ioctls that have their argument encoded in 'arg' instead
  of the memory pointed to by arg. Same reason as above.
- remove most #ifdefs in <linux/compat_ioctl.h>: They don't make
  any sense if the respective handlers in fs/compat_ioctl.c are
  not disabled as well and they are potentially harmful (the
  CONFIG_BLK_DEV_DM e.g. was insufficient).
- comment out  COMPATIBLE_IOCTL(SIOCSIFBR) and
  COMPATIBLE_IOCTL(SIOCGIFBR), they appear to require a handler
- implement copy_in_user for s390, as needed for many handlers in
  fs/compat_ioctl.c
- get rid of all duplicate stuff in arch/s390/kernel/compat_ioctl.c
  that is also in fs/compat_ioctl.c