mmc: sdhci-esdhc-imx: Fixup runtime PM conditions during ->probe()

By configure runtime PM prior we enable the use of it, we close the gap
for strange and unhandled conditions. Moreover it makes us rely on the
driver core, after finalized ->probe(), to request an inactive device
to become runtime PM idle/suspended, which earlier potentially could
happen already at pm_runtime_set_autosuspend_delay().

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>