ufs: move truncate code into inode.c

It is closely tied to block pointers handling there, can benefit
from existing helpers, etc. - no point keeping them apart.

Trimmed the trailing whitespaces in inode.c at the same time.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --cc fs/ufs/Makefile
Simple merge

diff --cc fs/ufs/inode.c
Simple merge

diff --cc fs/ufs/truncate.c
Simple merge

diff --cc fs/ufs/ufs.h
Simple merge