.gitignore: add SPDX License Identifier

Add SPDX License Identifier to all .gitignore files.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

.gitignore: move *.dtb and *.dtb.S patterns to the top-level .gitignore

Most of DT files are compiled under arch/*/boot/dts/, but we have some
other directories, like drivers/of/unittest-data/. We often miss to
add gitignore patterns per directory. Since there are no source files
that end with .dtb or .dtb.S, we can ignore the patterns globally.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Rob Herring <robh@kernel.org>

microblaze: Add .gitignore entries for auto-generated files

Add .gitignore entries for files which are generated during the build process.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>