mmc: dw_mmc: force setup bus if active slots exist

It's necessary to setup bus if any slots are present.
- update clock after ctrl reset
- if the host has genpd node, we can guarantee the clock is
  available before starting request. Otherwies, the clock register
  is reset once power off the pd, and host can't output the active
  clock during communication.

Fixes: e9ed8835e9 ("mmc: dw_mmc: add runtime PM callback")
Fixes: df9bcc2bc0 ("mmc: dw_mmc: add missing codes for runtime resume")
cc: <stable@vger.kernel.org>
Reported-by: Randy Li <randy.li@rock-chips.com>
Reported-by: S. Gilles <sgilles@math.umd.edu>
Signed-off-by: Ziyuan Xu <xzy.xu@rock-chips.com>
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/dw_mmc.c

@@ -3354,10 +3354,11 @@ int dw_mci_runtime_resume(struct device *dev)
 
 		if (!slot)
 			continue;
-		if (slot->mmc->pm_flags & MMC_PM_KEEP_POWER) {
+		if (slot->mmc->pm_flags & MMC_PM_KEEP_POWER)
 			dw_mci_set_ios(slot->mmc, &slot->mmc->ios);
-			dw_mci_setup_bus(slot, true);
-		}
+
+		/* Force setup bus to guarantee available clock output */
+		dw_mci_setup_bus(slot, true);
 	}
 
 	/* Now that slots are all setup, we can enable card detect */