arm64: Add Kconfig option for APM X-Gene SOC family

This patch adds arm64/Kconfig option for APM X-Gene SOC family.
Signed-off-by: Kumar Sankaran <ksankaran@apm.com>
Signed-off-by: Loc Ho <lho@apm.com>
Signed-off-by: Feng Kan <fkan@apm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/Kconfig

@@ -112,6 +112,11 @@ config ARCH_VEXPRESS
 	  This enables support for the ARMv8 software model (Versatile
 	  Express).
 
+config ARCH_XGENE
+	bool "AppliedMicro X-Gene SOC Family"
+	help
+	  This enables support for AppliedMicro X-Gene SOC Family
+
 endmenu
 
 menu "Bus support"
@@ -149,6 +154,8 @@ config NR_CPUS
 	int "Maximum number of CPUs (2-32)"
 	range 2 32
 	depends on SMP
+	# These have to remain sorted largest to smallest
+	default "8" if ARCH_XGENE
 	default "4"
 
 source kernel/Kconfig.preempt