LU-2675 llite: remove generic operations from llite/namei.c

LU-2675 llite: remove generic operations from llite/namei.c

Remove the llite inode operation wrappers ll_mknod(), ll_unlink(),
ll_mkdir(), ll_rmdir(), ll_symlink(), ll_link(), and ll_rename(),
replacing them with calls to ll_mknod_generic(), but rename these
functions to drop the _generic suffix. Remove several variables that
are always NULL after this transformation. Simplify some control flow,
using the knowledge that certain variables are never NULL. Replace
calls to ll_d_mountpoint() with equivalent calls to d_mountpoint() and
remove the then unused function ll_d_mountpoint(). Remove the
effectively unused lookup_flags parameter from ll_create_it().

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: Ib1757399c66a119e842d3361f184128ce2b96a78
Reviewed-on: http://review.whamcloud.com/10769
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Yang Sheng <yang.sheng@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>