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/configs/caddy2_defconfig b/configs/caddy2_defconfig
index 5fec4f8..fe0c34f 100644
--- a/configs/caddy2_defconfig
+++ b/configs/caddy2_defconfig
@@ -1,10 +1,9 @@
 CONFIG_PPC=y
 CONFIG_SYS_TEXT_BASE=0xFFF00000
 CONFIG_MPC83xx=y
-CONFIG_TARGET_VME8349=y
+CONFIG_TARGET_CADDY2=y
 CONFIG_OF_BOARD_SETUP=y
 CONFIG_OF_STDOUT_VIA_ALIAS=y
-CONFIG_SYS_EXTRA_OPTIONS="CADDY2"
 CONFIG_BOOTDELAY=6
 CONFIG_MISC_INIT_R=y
 CONFIG_HUSH_PARSER=y