arm64: make default NR_CPUS 8

Rather than continue to add per platform defaults, make the default a
likely common core count. 8 is also the default for x86.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/Kconfig

@@ -159,8 +159,7 @@ config NR_CPUS
 	range 2 32
 	depends on SMP
 	# These have to remain sorted largest to smallest
-	default "8" if ARCH_XGENE
-	default "4"
+	default "8"
 
 config HOTPLUG_CPU
 	bool "Support for hot-pluggable CPUs"