ARM: tegra: cpuidle: Remove unnecessary memory barrier

There is no good justification for smp_rmb() after returning from LP2
because there are no memory operations that require SMP synchronization.
Thus remove the confusing barrier.
Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Tested-by: Peter Geis <pgwipeout@gmail.com>
Tested-by: Jasper Korten <jja2000@gmail.com>
Tested-by: David Heidelberg <david@ixit.cz>
Tested-by: Nicolas Chauvet <kwizart@gmail.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm/mach-tegra/cpuidle-tegra20.c

@@ -197,8 +197,6 @@ static int tegra20_idle_lp2_coupled(struct cpuidle_device *dev,
 
 	local_fiq_enable();
 
-	smp_rmb();
-
 	return entered_lp2 ? index : 0;
 }
 #endif

arch/arm/mach-tegra/cpuidle-tegra30.c

@@ -113,8 +113,6 @@ static int tegra30_idle_lp2(struct cpuidle_device *dev,
 
 	local_fiq_enable();
 
-	smp_rmb();
-
 	return (entered_lp2) ? index : 0;
 }
 #endif