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/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
index b3193e6..29a546f 100644
--- a/sound/soc/soc-dapm.c
+++ b/sound/soc/soc-dapm.c
@@ -24,7 +24,7 @@
  *    o Automatic Mic Bias support
  *    o Jack insertion power event initiation - e.g. hp insertion will enable
  *      sinks, dacs, etc
- *    o Delayed powerdown of audio susbsytem to reduce pops between a quick
+ *    o Delayed powerdown of audio susbsystem to reduce pops between a quick
  *      device reopen.
  *
  *  Todo: