arm: introduce psci_smp_ops

Rename virt_smp_ops to psci_smp_ops and move them to arch/arm/kernel/psci_smp.c.
Remove mach-virt/platsmp.c, now unused.
Compile psci_smp if CONFIG_ARM_PSCI and CONFIG_SMP.

Add a cpu_die smp_op based on psci_ops.cpu_off.

Initialize PSCI before setting smp_ops in setup_arch.

If PSCI is available on the platform, prefer psci_smp_ops over the
platform smp_ops.


Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Will Deacon <will.deacon@arm.com>
CC: arnd@arndb.de
CC: marc.zyngier@arm.com
CC: linux@arm.linux.org.uk
CC: nico@linaro.org
CC: rob.herring@calxeda.com

diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 1522c7a..8f7a6e9 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -37,6 +37,7 @@
 #include <asm/cputype.h>
 #include <asm/elf.h>
 #include <asm/procinfo.h>
+#include <asm/psci.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
 #include <asm/smp_plat.h>
@@ -796,9 +797,13 @@
 	unflatten_device_tree();
 
 	arm_dt_init_cpu_maps();
+	psci_init();
 #ifdef CONFIG_SMP
 	if (is_smp()) {
-		smp_set_ops(mdesc->smp);
+		if (psci_smp_available())
+			smp_set_ops(&psci_smp_ops);
+		else if (mdesc->smp)
+			smp_set_ops(mdesc->smp);
 		smp_init_cpus();
 	}
 #endif