spi: tools: Add include folder to .gitignore

[ Upstream commit 5af56f30c4fcbade4a92f94dadfea517d1db9703 ]

The Makefile for the SPI tools creates an include/linux/spi folder and some
symlinks inside it. After running `make -C spi/tools`, this folder shows up
as untracked in the git status.
Add the above folder to the .gitignore file.

Fixes: f325b73dc4 ("spi: tools: move to tools buildsystem")
Signed-off-by: Francesco Lavra <flavra@baylibre.com>
Link: https://patch.msgid.link/20260209095001.556495-1-flavra@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Ulrich Hecht <uli@kernel.org>

tools/spi/.gitignore

@@ -1,2 +1,3 @@
 spidev_fdx
 spidev_test
+include/