powerpc: MPC8572: Remove macro CONFIG_MPC8572

Replace CONFIG_MPC8572 with ARCH_MPC8572 in Kconfig and clean up existing
macros.

Signed-off-by: York Sun <york.sun@nxp.com>
diff --git a/arch/powerpc/cpu/mpc85xx/Kconfig b/arch/powerpc/cpu/mpc85xx/Kconfig
index b58ccee..f4d9f9d 100644
--- a/arch/powerpc/cpu/mpc85xx/Kconfig
+++ b/arch/powerpc/cpu/mpc85xx/Kconfig
@@ -92,6 +92,7 @@
 
 config TARGET_MPC8572DS
 	bool "Support MPC8572DS"
+	select ARCH_MPC8572
 
 config TARGET_P1010RDB
 	bool "Support P1010RDB"
@@ -174,6 +175,7 @@
 
 config TARGET_XPEDITE537X
 	bool "Support xpedite537x"
+	select ARCH_MPC8572
 
 config TARGET_XPEDITE550X
 	bool "Support xpedite550x"
@@ -223,6 +225,9 @@
 config ARCH_MPC8569
 	bool
 
+config ARCH_MPC8572
+	bool
+
 source "board/freescale/b4860qds/Kconfig"
 source "board/freescale/bsc9131rdb/Kconfig"
 source "board/freescale/bsc9132qds/Kconfig"
diff --git a/arch/powerpc/cpu/mpc85xx/Makefile b/arch/powerpc/cpu/mpc85xx/Makefile
index 9df1434..e3f7dc8 100644
--- a/arch/powerpc/cpu/mpc85xx/Makefile
+++ b/arch/powerpc/cpu/mpc85xx/Makefile
@@ -71,7 +71,7 @@
 obj-$(CONFIG_ARCH_MPC8548) += mpc8548_serdes.o
 obj-$(CONFIG_ARCH_MPC8568) += mpc8568_serdes.o
 obj-$(CONFIG_ARCH_MPC8569) += mpc8569_serdes.o
-obj-$(CONFIG_MPC8572) += mpc8572_serdes.o
+obj-$(CONFIG_ARCH_MPC8572) += mpc8572_serdes.o
 obj-$(CONFIG_P1010)	+= p1010_serdes.o
 obj-$(CONFIG_P1011)	+= p1021_serdes.o
 obj-$(CONFIG_P1012)	+= p1021_serdes.o