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/net/spider_net.c b/drivers/net/spider_net.c
index 571060a..bccae7e 100644
--- a/drivers/net/spider_net.c
+++ b/drivers/net/spider_net.c
@@ -1639,7 +1639,7 @@
 
 /**
  * spider_net_interrupt - interrupt handler for spider_net
- * @irq: interupt number
+ * @irq: interrupt number
  * @ptr: pointer to net_device
  * @regs: PU registers
  *