kunit: add macro to allow conditionally exposing static symbols to tests

kunit: add macro to allow conditionally exposing static symbols to tests

[ Upstream commit 9c988fae6f6ae3224a568ab985881b66bb50c9ec ]

Create two macros:

VISIBLE_IF_KUNIT - A macro that sets symbols to be static if CONFIG_KUNIT
is not enabled. Otherwise if CONFIG_KUNIT is enabled there is no change to
the symbol definition.

EXPORT_SYMBOL_IF_KUNIT(symbol) - Exports symbol into
EXPORTED_FOR_KUNIT_TESTING namespace only if CONFIG_KUNIT is enabled. Must
use MODULE_IMPORT_NS(EXPORTED_FOR_KUNIT_TESTING) in test file in order to
use symbols.

Signed-off-by: Rae Moar <rmoar@google.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Stable-dep-of: 8884ba07786c ("apparmor: fix invalid reference on profile->disconnected")
Signed-off-by: Sasha Levin <sashal@kernel.org>