powerpc/qspinlock: Fix 32-bit build

Some 32-bit configurations don't pull in the spin_begin/end/relax
definitions. Fix is to restore a lost include.
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 84990b16 ("powerpc/qspinlock: add mcs queueing for contended waiters")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/oe-kbuild-all/202212050224.i7uh9fOh-lkp@intel.com
Link: https://lore.kernel.org/r/20221208123225.1566113-1-npiggin@gmail.com

arch/powerpc/lib/qspinlock.c

@@ -3,6 +3,7 @@
 #include <linux/compiler.h>
 #include <linux/export.h>
 #include <linux/percpu.h>
+#include <linux/processor.h>
 #include <linux/smp.h>
 #include <linux/topology.h>
 #include <linux/sched/clock.h>