bscan_proxies: vendor XCKU040 proxy bitstream (MIT, quartiq)

bscan_spi_xcku040.bit from quartiq/bscan_spi_bitstreams (c) QUARTIQ
GmbH, MIT — LICENSE.quartiq and README.md included for attribution.
Lets the BSCAN proxy path work out of the box on the KCU105.

bscan_proxies/LICENSE.quartiq

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2015-2021 QUARTIQ GmbH
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

bscan_proxies/README.md

@@ -0,0 +1,18 @@
+# BSCAN proxy bitstreams
+
+Pre-built "BSCAN proxy" bitstreams that bridge the JTAG `USER1`
+instruction to an FPGA's SPI flash pins (via a `BSCANE2` primitive),
+enabling fast SPI flashing — see `doc/tutorial.md`, Phase 2.5.
+
+These `.bit` files are **not** built here. They come from
+[quartiq/bscan_spi_bitstreams](https://github.com/quartiq/bscan_spi_bitstreams),
+© QUARTIQ GmbH, MIT-licensed — see `LICENSE.quartiq`. The host-side
+framing in `modules/bscan_spi/` matches OpenOCD's `jtagspi` so the same
+bitstreams work.
+
+| File | Part | Used by |
+|------|------|---------|
+| `bscan_spi_xcku040.bit` | Xilinx Kintex UltraScale XCKU040 | KCU105 |
+
+To add another part, drop the matching `bscan_spi_<part>.bit` here and
+point the registry entry's `proxy_bitstream` field at it.