.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>

selftests: ipc add missing generated file to .gitignore

Add missing generated file msgque to .gitignore

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

selftests: add missing .gitignore file or entry

Only IPC selftest is missing the .gitignore file, so add it.
Also step_after_suspend_test is missing in breakpoints selftest
.gitignore file

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>