bootstd: Remove prepared images

These are no-longer used. Drop them.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/test/py/tests/bootstd/flash1.img.xz b/test/py/tests/bootstd/flash1.img.xz
deleted file mode 100644
index 29b78c6..0000000
--- a/test/py/tests/bootstd/flash1.img.xz
+++ /dev/null
Binary files differ
diff --git a/test/py/tests/bootstd/mmc1.img.xz b/test/py/tests/bootstd/mmc1.img.xz
deleted file mode 100644
index cebf7b9..0000000
--- a/test/py/tests/bootstd/mmc1.img.xz
+++ /dev/null
Binary files differ
diff --git a/test/py/tests/bootstd/mmc4.img.xz b/test/py/tests/bootstd/mmc4.img.xz
deleted file mode 100644
index f4db011..0000000
--- a/test/py/tests/bootstd/mmc4.img.xz
+++ /dev/null
Binary files differ