[ spi_host, doc] Initial spec draft

Signed-off-by: Martin Lueker-Boden <martin.lueker-boden@wdc.com>
diff --git a/util/build_docs.py b/util/build_docs.py
index 4aa6e81..ead2c6a 100755
--- a/util/build_docs.py
+++ b/util/build_docs.py
@@ -78,6 +78,7 @@
         "hw/top_earlgrey/ip/rstmgr/data/autogen/rstmgr.hjson",
         "hw/top_earlgrey/ip/rv_plic/data/autogen/rv_plic.hjson",
         "hw/ip/rv_timer/data/rv_timer.hjson",
+        "hw/ip/spi_host/data/spi_host.hjson",
         "hw/ip/spi_device/data/spi_device.hjson",
         "hw/ip/sram_ctrl/data/sram_ctrl.hjson",
         "hw/ip/uart/data/uart.hjson",