powerpc: MPC8569: Remove macro CONFIG_MPC8569

Replace CONFIG_MPC8569 with ARCH_MPC8569 in Kconfig and clean up existing
macros.

Signed-off-by: York Sun <york.sun@nxp.com>
diff --git a/arch/powerpc/include/asm/config_mpc85xx.h b/arch/powerpc/include/asm/config_mpc85xx.h
index c38d983..c162c9d 100644
--- a/arch/powerpc/include/asm/config_mpc85xx.h
+++ b/arch/powerpc/include/asm/config_mpc85xx.h
@@ -113,7 +113,7 @@
 #define CONFIG_SYS_FSL_RMU
 #define CONFIG_SYS_FSL_SRIO_MSG_UNIT_NUM	2
 
-#elif defined(CONFIG_MPC8569)
+#elif defined(CONFIG_ARCH_MPC8569)
 #define CONFIG_MAX_CPUS			1
 #define CONFIG_SYS_FSL_NUM_LAWS		10
 #define CONFIG_SYS_FSL_SEC_COMPAT	2