dax: Fix alloc_dax_region() compile warning

PFN flags are (unsigned long long), fix the alloc_dax_region() calling
convention to fix warnings of the form:

>> include/linux/pfn_t.h:18:17: warning: large integer implicitly truncated to unsigned type [-Woverflow]
    #define PFN_DEV (1ULL << (BITS_PER_LONG_LONG - 3))

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index 8fafbeab..eccdda1 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -227,7 +227,7 @@ static void dax_region_unregister(void *region)
 
 struct dax_region *alloc_dax_region(struct device *parent, int region_id,
 		struct resource *res, int target_node, unsigned int align,
-		unsigned long pfn_flags)
+		unsigned long long pfn_flags)
 {
 	struct dax_region *dax_region;
 
diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h
index 8619e329..9e4eba6 100644
--- a/drivers/dax/bus.h
+++ b/drivers/dax/bus.h
@@ -11,7 +11,7 @@ struct dax_region;
 void dax_region_put(struct dax_region *dax_region);
 struct dax_region *alloc_dax_region(struct device *parent, int region_id,
 		struct resource *res, int target_node, unsigned int align,
-		unsigned long flags);
+		unsigned long long flags);
 
 enum dev_dax_subsys {
 	DEV_DAX_BUS,
diff --git a/drivers/dax/dax-private.h b/drivers/dax/dax-private.h
index 6ccca3b..3107ce8 100644
--- a/drivers/dax/dax-private.h
+++ b/drivers/dax/dax-private.h
@@ -32,7 +32,7 @@ struct dax_region {
 	struct device *dev;
 	unsigned int align;
 	struct resource res;
-	unsigned long pfn_flags;
+	unsigned long long pfn_flags;
 };
 
 /**