Adding information about ql_dsp command

Signed-off-by: Samy <samy.charas@cpe.fr>
diff --git a/README.md b/README.md
index 4721300..0e3fc84 100644
--- a/README.md
+++ b/README.md
@@ -63,6 +63,7 @@
 
 The plugin adds the following command:
 * synth_quicklogic
+* ql_dsp
 
 Detailed help on the supported command(s) can be obtained by running `help <command_name>` in Yosys.