Rename pmd to pmd_io

This better reflects the function of the module (interfacing the
transciever via the I/O pins), and fits better with the naming scheme
used for other I/O modules.

Signed-off-by: Sean Anderson <seanga2@gmail.com>

Makefile

@@ -63,7 +63,7 @@ endef
 %.post.fst: rtl/%.post.vvp tb/%.py FORCE
 	$(run-vvp)
 
-MODULES := pcs pmd nrzi_encode nrzi_decode scramble descramble mdio mdio_io mii_io_rx mii_io_tx
+MODULES := pcs pmd_io nrzi_encode nrzi_decode scramble descramble mdio mdio_io mii_io_rx mii_io_tx
 
 .PHONY: test
 test: $(addsuffix .fst,$(MODULES)) $(addsuffix .post.fst,$(MODULES))

rtl/pmd_io.v

@@ -13,7 +13,7 @@
 
 `timescale 1ns/1ps
 
-module pmd (
+module pmd_io (
 	input tx_clk,
 	input rx_clk_250,
 	input rx_clk_125,