arm64: dts: Fix various entry-method properties to reflect documentation

The idle-states binding documentation[1] mentions that the
'entry-method' property is required on 64-bit platforms and must be
set to "psci".

commit a13f18f59d ("Documentation: arm: Fix typo in the idle-states
bindings examples") attempted to fix this earlier but clearly more is
needed.

Fix the cpu-capacity.txt documentation that uses the incorrect value so
we don't get copy-paste errors like these. Clarify the language in
idle-states.txt by removing the reference to the psci bindings that
might be causing this confusion.

Finally, fix devicetrees of various boards to reflect current
documentation.

[1] Documentation/devicetree/bindings/arm/idle-states.txt (see
idle-states node)

Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Li Yang <leoyang.li@nxp.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

Documentation/devicetree/bindings/arm/cpu-capacity.txt

@@ -94,7 +94,7 @@ cpus {
 	};
 
 	idle-states {
-		entry-method = "arm,psci";
+		entry-method = "psci";
 
 		CPU_SLEEP_0: cpu-sleep-0 {
 			compatible = "arm,idle-state";

Documentation/devicetree/bindings/arm/idle-states.txt

@@ -237,8 +237,8 @@ processor idle states, defined as device tree nodes, are listed.
 		Value type: <stringlist>
 		Usage and definition depend on ARM architecture version.
 			# On ARM v8 64-bit this property is required and must
-			  be one of:
-			   - "psci" (see bindings in [2])
+			  be:
+			   - "psci"
 			# On ARM 32-bit systems this property is optional
 
 The nodes describing the idle states (state) can only be defined within the