The HAVE_MUTEX_OWNER_TASK_STRUCT fails on PPC64 with the following
error:
error: 'current' undeclared (first use in this function)
We include linux/sched.h to ensure that current is available.
Signed-off-by: Richard Yao <ryao@cs.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>