arch/csky: add support for the ck860 core

ck860 is newest CPU core of C-SKY with high performance & SMP
supported.

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

arch/Config.in.csky

@@ -13,11 +13,14 @@ config BR2_ck807
 config BR2_ck810
 	bool "ck810"
 
+config BR2_ck860
+	bool "ck860"
+
 endchoice
 
 config BR2_CSKY_FPU
 	bool "Enable FPU coprocessor"
-	depends on BR2_ck810 || BR2_ck807
+	depends on BR2_ck810 || BR2_ck807 || BR2_ck860
 	help
 	  You can say N here if your C-SKY CPU doesn't have a
 	  Floating-Point Coprocessor or if you don't need FPU support

arch/arch.mk.csky

@@ -11,6 +11,8 @@ else ifeq ($(BR2_ck807),y)
 GCC_TARGET_CPU := ck807
 else ifeq ($(BR2_ck810),y)
 GCC_TARGET_CPU := ck810
+else ifeq ($(BR2_ck860),y)
+GCC_TARGET_CPU := ck860
 endif
 
 ifeq ($(BR2_CSKY_FPU),y)