device property: build kunit tests without structleak plugin

The structleak plugin causes the stack frame size to grow immensely when
used with KUnit:

../drivers/base/test/property-entry-test.c:492:1: warning: the frame size of 2832 bytes is larger than 2048 bytes [-Wframe-larger-than=]
../drivers/base/test/property-entry-test.c:322:1: warning: the frame size of 2080 bytes is larger than 2048 bytes [-Wframe-larger-than=]
../drivers/base/test/property-entry-test.c:250:1: warning: the frame size of 4976 bytes is larger than 2048 bytes [-Wframe-larger-than=]
../drivers/base/test/property-entry-test.c:115:1: warning: the frame size of 3280 bytes is larger than 2048 bytes [-Wframe-larger-than=]

Turn it off in this file.

Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>