refperf: Adjust refperf.loop default value

With the various measurement optimizations, 10,000 loops normally
suffices.  This commit therefore reduces the refperf.loops default value
from 10,000,000 to 10,000.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

kernel/rcu/refperf.c

@@ -61,7 +61,7 @@ torture_param(int, verbose, 0, "Enable verbose debugging printk()s");
 torture_param(int, holdoff, IS_BUILTIN(CONFIG_RCU_REF_PERF_TEST) ? 10 : 0,
 	      "Holdoff time before test start (s)");
 // Number of loops per experiment, all readers execute operations concurrently.
-torture_param(long, loops, 10000000, "Number of loops per experiment.");
+torture_param(long, loops, 10000, "Number of loops per experiment.");
 // Number of readers, with -1 defaulting to about 75% of the CPUs.
 torture_param(int, nreaders, -1, "Number of readers, -1 for 75% of CPUs.");
 // Number of runs.