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/cpu/mpc85xx/Makefile b/arch/powerpc/cpu/mpc85xx/Makefile
index 939f681..a663379 100644
--- a/arch/powerpc/cpu/mpc85xx/Makefile
+++ b/arch/powerpc/cpu/mpc85xx/Makefile
@@ -81,7 +81,7 @@
 obj-$(CONFIG_P1020)	+= p1021_serdes.o
 obj-$(CONFIG_P1021)	+= p1021_serdes.o
 obj-$(CONFIG_ARCH_P1022)	+= p1022_serdes.o
-obj-$(CONFIG_P1023)	+= p1023_serdes.o
+obj-$(CONFIG_ARCH_P1023)	+= p1023_serdes.o
 obj-$(CONFIG_P1024)	+= p1021_serdes.o
 obj-$(CONFIG_P1025)	+= p1021_serdes.o
 obj-$(CONFIG_P2010)	+= p2020_serdes.o