LU-10560 libcfs: remove extra headers from linux-debug.c

LU-10560 libcfs: remove extra headers from linux-debug.c

Remove headers from linux-debug.c that are no longer (or were possibly
never) needed.  This avoids a compile problem with 4.14 kernels:

  CC [M] lustre/libcfs/libcfs/linux/linux-debug.o
  In file included from lustre/libcfs/libcfs/linux/linux-debug.c:50:0:
    ./arch/x86/include/asm/uaccess.h:31:9: In function set_fs():
      error: dereferencing pointer to incomplete type
      current->thread.addr_limit = fs;

It turns out <asm/uaccess.h> was included twice but we don't need
anything from that header.  Same for <linux/stat.h> and a number of
other extraneous headers.

Sort headers alphabetically so it is easier to avoid duplicates.

Test-Parameters: trivial
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: I751e796913624cd8c9c95052abe4ecbb823ebbe5
Reviewed-on: https://review.whamcloud.com/31007
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>