drivers/dax/device.c: convert variable to vm_fault_t type

As part of 226ab56 ("device-dax: Convert to vmf_insert_mixed and
vm_fault_t") in 4.19-rc1, 'rc' was not converted to vm_fault_t.  Now
converted.

Link: http://lkml.kernel.org/r/20180830153813.GA26059@jordon-HP-15-Notebook-PC
Signed-off-by: Souptick Joarder <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Dave Jiang <[email protected]>
Cc: Ross Zwisler <[email protected]>
Cc: Vishal Verma <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: Souptick Joarder

drivers/dax/device.c

@@ -392,7 +392,8 @@ static vm_fault_t dev_dax_huge_fault(struct vm_fault *vmf,
 {
 	struct file *filp = vmf->vma->vm_file;
 	unsigned long fault_size;
-	int rc, id;
+	vm_fault_t rc = VM_FAULT_SIGBUS;
+	int id;
 	pfn_t pfn;
 	struct dev_dax *dev_dax = filp->private_data;