ARM: tegra: Do not fully reinitialize L2 on resume

ASUS TF300T device may not work properly if firmware is asked to fully
re-initialize L2 cache after resume from LP2 suspend. The downstream
kernel of TF300T uses different opcode to enable cache after resuming
from LP2, this opcode also works fine on Nexus 7 and Ouya devices.
Supposedly, this may be needed by an older firmware versions.

Reported-by: Michał Mirosław <[email protected]>
Tested-by: Michał Mirosław <[email protected]>
Tested-by: Jasper Korten <[email protected]>
Tested-by: David Heidelberg <[email protected]>
Tested-by: Peter Geis <[email protected]>
Signed-off-by: Dmitry Osipenko <[email protected]>
Signed-off-by: Thierry Reding <[email protected]>

Author: digetx

arch/arm/mach-tegra/pm.c

@@ -216,6 +216,8 @@ int tegra_pm_enter_lp2(void)
 	restore_cpu_complex();
 	cpu_cluster_pm_exit();
 
+	call_firmware_op(prepare_idle, TF_PM_MODE_NONE);
+
 	return err;
 }
 
@@ -391,6 +393,8 @@ static int tegra_suspend_enter(suspend_state_t state)
 
 	local_fiq_enable();
 
+	call_firmware_op(prepare_idle, TF_PM_MODE_NONE);
+
 	return 0;
 }