debugfs: use the functions in misc/create_inode.c

debugfs: use the functions in misc/create_inode.c

* Use the functions in misc/create_inode.c, and remove the duplicated
  code.

* The CREATE_INODE_DEPS in the debugfs/Makefile.in is used for recording
  create_inode.o's depends which is from misc/Makefile.in, we have to
  recompile create_inode.o because we need it to print more messages when
  it is used by debugfs, just like we recompile e2freefrag.o, but it seems
  that the e2freefrag.o's depends in debugfs/Makefile.in is incorrect, it
  would not rebuild when its depends (e.g.: lib/config.h) is changed,
  which would cause unexpected errors. Make duplicated code in
  debugfs/Makefile.in and misc/Makefile.in is not a good idea, maybe we'd
  better define CREATE_INODE_DEPS in the top Makefile, I'd like to send
  another patch and fix the e2freefrag if you are fine with it.

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Reviewed-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>