mmc: omap_hsmmc: Get rid of of_have_populated_dt() usage

of_have_populated_dt() is not expected to be used in drivers but
instead only in early platform init code.
Drivers on the other hand should rely on dev->of_node or of_match_device().
Besides usage of of_have_populated_dt() also throws up build error as below
which was reported by Balaji TK, when omap_hsmmc is built as a module.

ERROR: "allnodes" [drivers/mmc/host/omap_hsmmc.ko] undefined!
make[1]: *** [__modpost] Error 1
make: *** [modules] Error 2

So get rid of all of_have_populated_dt() usage in omap_hsmmc driver and
instead use dev->of_node to make the same dicisions as earlier.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Reported-by: Benoit Cousson <b-cousson@ti.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Reviewed-by: Balaji T K <balajitk@ti.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/host/omap_hsmmc.c

@@ -249,7 +249,7 @@ static int omap_hsmmc_set_power(struct device *dev, int slot, int power_on,
 	 * the pbias cell programming support is still missing when
 	 * booting with Device tree
 	 */
-	if (of_have_populated_dt() && !vdd)
+	if (dev->of_node && !vdd)
 		return 0;
 
 	if (mmc_slot(host).before_set_reg)
@@ -1549,7 +1549,7 @@ static void omap_hsmmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 			 * can't be allowed when booting with device
 			 * tree.
 			 */
-			(!of_have_populated_dt())) {
+			!host->dev->of_node) {
 				/*
 				 * The mmc_select_voltage fn of the core does
 				 * not seem to set the power_mode to