BugLink: https://bugs.launchpad.net/bugs/1878232

commit 27d80fa8 upstream.

Driver enabled runtime PM but did not revert this on removal. Re-binding
of a device triggered warning:
	exynos-rng 10830400.rng: Unbalanced pm_runtime_enable!

Fixes: b329669e ("hwrng: exynos - Add support for Exynos random number generator")
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ian May <ian.may@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>