powerpc: MPC8610: Remove macro CONFIG_MPC8610

Replace CONFIG_MPC8610 with ARCH_MPC8610 in Kconfig and clean up
existing macros.

Signed-off-by: York Sun <york.sun@nxp.com>
diff --git a/arch/powerpc/cpu/mpc86xx/Kconfig b/arch/powerpc/cpu/mpc86xx/Kconfig
index fe1859d..c3b3b07 100644
--- a/arch/powerpc/cpu/mpc86xx/Kconfig
+++ b/arch/powerpc/cpu/mpc86xx/Kconfig
@@ -13,6 +13,7 @@
 
 config TARGET_MPC8610HPCD
 	bool "Support MPC8610HPCD"
+	select ARCH_MPC8610
 
 config TARGET_MPC8641HPCN
 	bool "Support MPC8641HPCN"
@@ -22,6 +23,9 @@
 
 endchoice
 
+config ARCH_MPC8610
+	bool
+
 source "board/freescale/mpc8610hpcd/Kconfig"
 source "board/freescale/mpc8641hpcn/Kconfig"
 source "board/sbc8641d/Kconfig"
diff --git a/arch/powerpc/cpu/mpc86xx/Makefile b/arch/powerpc/cpu/mpc86xx/Makefile
index 0f790b0..0caf9f1 100644
--- a/arch/powerpc/cpu/mpc86xx/Makefile
+++ b/arch/powerpc/cpu/mpc86xx/Makefile
@@ -19,6 +19,6 @@
 obj-$(CONFIG_OF_LIBFDT) += fdt.o
 obj-y	+= interrupts.o
 obj-$(CONFIG_MP) += mp.o
-obj-$(CONFIG_MPC8610) += mpc8610_serdes.o
+obj-$(CONFIG_ARCH_MPC8610) += mpc8610_serdes.o
 obj-$(CONFIG_MPC8641) += mpc8641_serdes.o
 obj-y	+= speed.o
diff --git a/arch/powerpc/cpu/mpc86xx/cpu.c b/arch/powerpc/cpu/mpc86xx/cpu.c
index 3051854..4dc483b 100644
--- a/arch/powerpc/cpu/mpc86xx/cpu.c
+++ b/arch/powerpc/cpu/mpc86xx/cpu.c
@@ -90,7 +90,7 @@
 
 	puts("L2:    ");
 	if (get_l2cr() & 0x80000000) {
-#if defined(CONFIG_MPC8610)
+#if defined(CONFIG_ARCH_MPC8610)
 		puts("256");
 #elif defined(CONFIG_MPC8641)
 		puts("512");
@@ -139,7 +139,7 @@
 void
 watchdog_reset(void)
 {
-#if defined(CONFIG_MPC8610)
+#if defined(CONFIG_ARCH_MPC8610)
 	/*
 	 * This actually feed the hard enabled watchdog.
 	 */
diff --git a/arch/powerpc/cpu/mpc86xx/speed.c b/arch/powerpc/cpu/mpc86xx/speed.c
index 5abe6f0..05f23db 100644
--- a/arch/powerpc/cpu/mpc86xx/speed.c
+++ b/arch/powerpc/cpu/mpc86xx/speed.c
@@ -115,7 +115,7 @@
 	 * for that SOC. This information is taken from application note
 	 * AN2919.
 	 */
-#ifdef CONFIG_MPC8610
+#ifdef CONFIG_ARCH_MPC8610
 	gd->arch.i2c1_clk = sys_info.freq_systembus;
 #else
 	gd->arch.i2c1_clk = sys_info.freq_systembus / 2;