fix: sched: Change task_struct::state (v5.14)

See upstream commit:

  commit 2f064a59a11ff9bc22e52e9678bc601404c7cb34
  Author: Peter Zijlstra <peterz@infradead.org>
  Date:   Fri Jun 11 10:28:17 2021 +0200

    sched: Change task_struct::state

    Change the type and name of task_struct::state. Drop the volatile and
    shrink it to an 'unsigned int'. Rename it in order to find all uses
    such that we can use READ_ONCE/WRITE_ONCE as appropriate.

Change-Id: I3a379192d6b977753fe58d4f67833a78dd7a0a47
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>