LU-9010 ptlrpc: Change static defines to use macro for gss_krb5_mech.c

LU-9010 ptlrpc: Change static defines to use macro for gss_krb5_mech.c

This patch replaces spinlock which are defined statically
in file lustre/ptlrpc/gss/gss_krb5_mech.c with kernel provided macro.

Signed-off-by: Arshad Hussain <arshad.super@gmail.com>
Change-Id: I5da319ce013c29043fc4bde4a4946cfbdf6c2491
Reviewed-on: https://review.whamcloud.com/33936
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Ben Evans <bevans@cray.com>
Reviewed-by: Sebastien Buisson <sbuisson@ddn.com>
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>