mmc: mmci: Let runtime PM callbacks be available for CONFIG_PM

Convert to the SET_PM_RUNTIME_PM macro while defining the runtime PM
callbacks. This means the callbacks becomes available for both
CONFIG_PM_SLEEP and CONFIG_PM_RUNTIME, which is needed to handle the
combinations of these scenarios.

Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>