ARM: exynos_defconfig: Enable PM_DEBUG

PM_DEBUG and PM_ADVANCED_DEBUG bring some information useful for
development and they should not cause any significant overhead.  Enable
them in default configuration so debugging would be slightly easier.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Acked-by: Kukjin Kim <kgene@kernel.org>