Condense similar type file listings in directory structure.

README.md

diff --git a/README.md b/README.md
index eb2c15b..aecdddb 100644
--- a/README.md
+++ b/README.md
@@ -90,9 +90,7 @@
          |
           - addressalyzer.v
          |
-          - spi_passthrough.v
-         |
-          - spi_slave_des.v
+          - spi_*.v
          |
           - register_bank.v
                |