mpc83xx: Make distinct caddy2 config

vme8349.h contains two separate boards: The vme8349 itself, and the
caddy2 board. The caddy2 board is chosen by setting certain config
variables. Create a proper config file for the caddy2 board to make
Kconfig migration easier.

Furthermore, simplify the vme8349 and caddy2 configs by keeping only the
options necessary for each board.

Signed-off-by: Mario Six <mario.six@gdsys.cc>
diff --git a/arch/powerpc/cpu/mpc83xx/Kconfig b/arch/powerpc/cpu/mpc83xx/Kconfig
index ede98c7..65f4583 100644
--- a/arch/powerpc/cpu/mpc83xx/Kconfig
+++ b/arch/powerpc/cpu/mpc83xx/Kconfig
@@ -24,6 +24,10 @@
 	bool "Support vme8349"
 	select ARCH_MPC8349
 
+config TARGET_CADDY2
+	bool "Support caddy2"
+	select ARCH_MPC8349
+
 config TARGET_MPC8308RDB
 	bool "Support MPC8308RDB"
 	select ARCH_MPC8308