soc: samsung: exynos-pmu: fix device leak on regmap lookup

soc: samsung: exynos-pmu: fix device leak on regmap lookup

Make sure to drop the reference taken when looking up the PMU device and
its regmap.

Note that holding a reference to a device does not prevent its regmap
from going away so there is no point in keeping the reference.

Fixes: 0b7c6075022c ("soc: samsung: exynos-pmu: Add regmap support for SoCs that protect PMU regs")
Cc: stable@vger.kernel.org	# 6.9
Cc: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20251121121852.16825-1-johan@kernel.org
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>