xen-blkfront: Silence pfn maybe-uninitialized warning
xen-blkfront: Silence pfn maybe-uninitialized warning

pfn cannot actually be used unless (!info->feature_persistent), nor is
pfn accessed in get_grant() unless (!info->feature_persistent), but silence
this warning anyway. gcc-4.8

drivers/block/xen-blkfront.c: In function 'do_blkif_request':
drivers/block/xen-blkfront.c:508:20: warning: 'pfn' may be used uninitialized in this function [-Wmaybe-uninitialized]
     gnt_list_entry = get_grant(&gref_head, pfn, info);
                    ^
drivers/block/xen-blkfront.c:492:19: note: 'pfn' was declared here
     unsigned long pfn;

Cc: Konrad Rzeszutek Wilk <da3a51b335cef0eb0e2c329c5ef6bcd6acef687a@oracle.com>
Cc: Boris Ostrovsky <b41c17b861974b03cec38e3ec2992769b9bfae55@oracle.com>
Cc: David Vrabel <b9d45bd1f671e508cd8daa63dfc3cabb597562df@citrix.com>
Signed-off-by: Tim Gardner <c65a040f7f664378353fb65fc3553df208a14f68@canonical.com>
Signed-off-by: Konrad Rzeszutek Wilk <da3a51b335cef0eb0e2c329c5ef6bcd6acef687a@oracle.com>
Acked-by: Roger Pau Monné <1c35b25b17252e1e5021df00666589fc74f64580@citrix.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs