Fix typos concerning hierarchy

        heirarchical, hierachical -> hierarchical
        heirarchy, hierachy -> hierarchy

Signed-off-by: Uwe Kleine-König <zeisberg@informatik.uni-freiburg.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt
index 7ba2baa..5daa2aa 100644
--- a/Documentation/filesystems/sysfs-pci.txt
+++ b/Documentation/filesystems/sysfs-pci.txt
@@ -65,7 +65,7 @@
 ----------------------------------------
 
 Legacy I/O port and ISA memory resources are also provided in sysfs if the
-underlying platform supports them.  They're located in the PCI class heirarchy,
+underlying platform supports them.  They're located in the PCI class hierarchy,
 e.g.
 
 	/sys/class/pci_bus/0000:17/