ppc: Remove T4160RDB board

This board has not been converted to CONFIG_DM_PCI by the deadline and is
also missing conversion to CONFIG_DM.  Remove it.  As this is the last
ARCH_T4160 platform, remove that support as well.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/board/freescale/t4rdb/Kconfig b/board/freescale/t4rdb/Kconfig
index a94a57e..542e574 100644
--- a/board/freescale/t4rdb/Kconfig
+++ b/board/freescale/t4rdb/Kconfig
@@ -1,4 +1,4 @@
-if TARGET_T4160RDB || TARGET_T4240RDB
+if TARGET_T4240RDB
 
 config SYS_BOARD
 	default "t4rdb"