Add bb_spi_controller

Bit banged spi controller, very simple but very slow.

hw/fpga/simulation/modelsim/bb_spi_testbench.do

@@ -0,0 +1,24 @@
+transcript on
+if {[file exists rtl_work]} {
+	vdel -lib rtl_work -all
+}
+vlib rtl_work
+vmap work rtl_work
+
+vlog -sv -work work  {../../bb_spi_controller.sv}
+vlog -sv -work work  {../../hvl/bb_spi_testbench.sv}
+
+vsim -t 1ps -L altera_ver -L lpm_ver -L sgate_ver -L altera_mf_ver -L altera_lnsim_ver -L stratixv_ver -L stratixv_hssi_ver -L stratixv_pcie_hip_ver -L rtl_work -L work -voptargs="+acc"  testbench
+
+add wave -group {dut} -radix hexadecimal sim:/testbench/dut/*
+
+onfinish stop
+run -all
+
+if { [coverage attribute -name TESTSTATUS -concise] == "1"} {
+    echo Warning
+    quit -f -code 0
+}
+
+quit -code [coverage attribute -name TESTSTATUS -concise]
+