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

arch/arm/mach-tegra/pm.c

···
 	restore_cpu_complex();
 	cpu_cluster_pm_exit();
 
+	call_firmware_op(prepare_idle, TF_PM_MODE_NONE);
+
 	return err;
 }
 
···
 	restore_cpu_complex();
 
 	local_fiq_enable();
+
+	call_firmware_op(prepare_idle, TF_PM_MODE_NONE);
 
 	return 0;
 }