xdc-plugin: fix missing IOBUFDS

Signed-off-by: Alessandro Comodi <acomodi@antmicro.com>

xdc-plugin/xdc.cc

diff --git a/xdc-plugin/xdc.cc b/xdc-plugin/xdc.cc
index 9a8e5e7..8dd72c2 100644
--- a/xdc-plugin/xdc.cc
+++ b/xdc-plugin/xdc.cc
@@ -61,7 +61,8 @@
 	{"OBUFDS", {"IO_LOC_PAIRS", "IOSTANDARD", "SLEW", "IN_TERM"}},
 	{"OBUFTDS", {"IO_LOC_PAIRS", "IOSTANDARD", "SLEW", "IN_TERM"}},
 	{"IBUF", {"IO_LOC_PAIRS", "IOSTANDARD"}},
-	{"IOBUF", {"IO_LOC_PAIRS", "IOSTANDARD", "DRIVE", "SLEW", "IN_TERM"}}
+	{"IOBUF", {"IO_LOC_PAIRS", "IOSTANDARD", "DRIVE", "SLEW", "IN_TERM"}},
+	{"IOBUFDS", {"IO_LOC_PAIRS", "IOSTANDARD", "SLEW", "IN_TERM"}}
 };
 
 void register_in_tcl_interpreter(const std::string& command) {