Fix misspellings of "system", "controller", "interrupt" and "necessary".

Fix the various misspellings of "system", controller", "interrupt" and
"[un]necessary".

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
diff --git a/arch/powerpc/platforms/celleb/scc_uhc.c b/arch/powerpc/platforms/celleb/scc_uhc.c
index a7c548b..b59c38a 100644
--- a/arch/powerpc/platforms/celleb/scc_uhc.c
+++ b/arch/powerpc/platforms/celleb/scc_uhc.c
@@ -36,7 +36,7 @@
 }
 
 /*
- * UHC(usb host controler) enable function.
+ * UHC(usb host controller) enable function.
  * affect to both of OHCI and EHCI core module.
  */
 static void enable_scc_uhc(struct pci_dev *dev)