Add support for PSCI SYSTEM_OFF and SYSTEM_RESET APIs

This patch adds support for SYSTEM_OFF and SYSTEM_RESET PSCI
operations. A platform should export handlers to complete the
requested operation. The FVP port exports fvp_system_off() and
fvp_system_reset() as an example.

If the SPD provides a power management hook for system off and
system reset, then the SPD is notified about the corresponding
operation so it can do some bookkeeping. The TSPD exports
tspd_system_off() and tspd_system_reset() for that purpose.

Versatile Express shutdown and reset methods have been removed
from the FDT as new PSCI sys_poweroff and sys_reset services
have been added. For those kernels that do not support yet these
PSCI services (i.e. GICv3 kernel), the original dtsi files have
been renamed to *-no_psci.dtsi.

Fixes ARM-software/tf-issues#218

Change-Id: Ic8a3bf801db979099ab7029162af041c4e8330c8
diff --git a/fdts/fvp-foundation-gicv2-psci.dts b/fdts/fvp-foundation-gicv2-psci.dts
index 8f3de9d..8d354b3 100644
--- a/fdts/fvp-foundation-gicv2-psci.dts
+++ b/fdts/fvp-foundation-gicv2-psci.dts
@@ -57,6 +57,8 @@
 		cpu_suspend = <0xc4000001>;
 		cpu_off = <0x84000002>;
 		cpu_on = <0xc4000003>;
+		sys_poweroff = <0x84000008>;
+		sys_reset = <0x84000009>;
 	};
 
 	cpus {