[PATCH] prepare for 32-bit dev_t: stat()

[PATCH] prepare for 32-bit dev_t: stat()

	Added old_encode_dev() to assorted stat() variants.
	Fixed bug in s390 emulation on s390x: stat64() should never truncate
UID and GID.
	Ditto for i386 emulation on x86_64.
	Replaced dev_t in various struct stat with explicit integer type.
	Replaced __kernel_dev_t with __old_kernel_dev_t in dm-ioctl-v1.h
	Now we are free to change dev_t in any way we want - on all boundaries
we have explicit conversions.
	Took __kernel_dev_t definition to linux/types.h and changed it with
__u16.  We are ready to proceed to 32bit now.