spi: fsl-(e)spi: migrate to using devm_ functions to simplify cleanup

Migrate fsl-espi and fsl-spi to using the managed devm_ functions
for resource handling. This simplifies the cleanup.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>