powerpc: P1023: Remove macro CONFIG_P1023

Replace CONFIG_P1023 with ARCH_P1023 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 471d27a..8ad503e 100644
--- a/arch/powerpc/include/asm/config_mpc85xx.h
+++ b/arch/powerpc/include/asm/config_mpc85xx.h
@@ -298,7 +298,7 @@
 #define CONFIG_SYS_FSL_ERRATUM_A005125
 #define CONFIG_SYS_FSL_ERRATUM_A004477
 
-#elif defined(CONFIG_P1023)
+#elif defined(CONFIG_ARCH_P1023)
 #define CONFIG_MAX_CPUS			2
 #define CONFIG_SYS_FSL_NUM_LAWS		12
 #define CONFIG_SYS_FSL_SEC_COMPAT	4