irmap: Properly compare stat vs proc devices

The s_dev value we see in irmap is get from proc file and is
raw kernel dev_t. We compare this value to the device get from
stat syscall, which is old-style dev_t (with less bits for minor).

Thus, need to convert kernel dev_t to stat's dev_t for proper
comparison.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

irmap.c

@@ -212,6 +212,8 @@ char *irmap_lookup(unsigned int s_dev, unsigned long i_ino)
 	char *path = NULL;
 	int hv;
 
+	s_dev = kdev_to_odev(s_dev);
+
 	pr_debug("Resolving %x:%lx path\n", s_dev, i_ino);
 
 	timing_start(TIME_IRMAP_RESOLVE);