board: .gitignore: ignore board-specific generated files

Ignore
  - board/cray/L1/bootscript.{c|image}
  - board/matrix_vision/mvblm7/bootscript.img
  - board/maxtir_vision/mvsmr/bootscript.img

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Andre Schwarz <andre.schwarz@matrix-vision.de>
diff --git a/board/cray/L1/.gitignore b/board/cray/L1/.gitignore
new file mode 100644
index 0000000..cd76d66
--- /dev/null
+++ b/board/cray/L1/.gitignore
@@ -0,0 +1,2 @@
+bootscript.c
+bootscript.image