powerpc: cyrus: Separate P5020/P5040 config options

Instead of using EXTRA options in defconfig, use two targets
in Kconfig to select correct SoC.

Signed-off-by: York Sun <york.sun@nxp.com>
diff --git a/arch/powerpc/cpu/mpc85xx/Kconfig b/arch/powerpc/cpu/mpc85xx/Kconfig
index 3ee7d2f..9a5cd85 100644
--- a/arch/powerpc/cpu/mpc85xx/Kconfig
+++ b/arch/powerpc/cpu/mpc85xx/Kconfig
@@ -309,8 +309,14 @@
 	bool "Support uCP1020"
 	select ARCH_P1020
 
-config TARGET_CYRUS
-	bool "Support Varisys Cyrus"
+config TARGET_CYRUS_P5020
+	bool "Support Varisys Cyrus P5020"
+	select ARCH_P5020
+	select PHYS_64BIT
+
+config TARGET_CYRUS_P5040
+	 bool "Support Varisys Cyrus P5040"
+	select ARCH_P5040
 	select PHYS_64BIT
 
 endchoice