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/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index 0dcb416..735db4a 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -451,7 +451,7 @@
 
 	/* Some boards (mostly VIA?) report bogus overcurrent indications,
 	 * causing massive log spam unless we completely ignore them.  It
-	 * may be relevant that VIA VT8235 controlers, where PORT_POWER is
+	 * may be relevant that VIA VT8235 controllers, where PORT_POWER is
 	 * always set, seem to clear PORT_OCC and PORT_CSC when writing to
 	 * PORT_POWER; that's surprising, but maybe within-spec.
 	 */