arm64: dts: Reserve the memory used for secondary CPU release address

With the spin-table SMP booting method, secondary CPUs poll a location
passed in the DT. The foundation-v8.dts file doesn't have this memory
reserved and there is a risk of Linux using it before secondary CPUs are
started.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

arch/arm64/boot/dts/foundation-v8.dts

@@ -6,6 +6,8 @@
 
 /dts-v1/;
 
+/memreserve/ 0x80000000 0x00010000;
+
 / {
 	model = "Foundation-v8A";
 	compatible = "arm,foundation-aarch64", "arm,vexpress";