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/mips/sni/pcimt.c b/arch/mips/sni/pcimt.c
index 39bb15f..4df070f 100644
--- a/arch/mips/sni/pcimt.c
+++ b/arch/mips/sni/pcimt.c
@@ -246,7 +246,7 @@
 		/*
 		 * Note: ASIC PCI's builtin interrupt achknowledge feature is
 		 * broken.  Using it may result in loss of some or all i8259
-		 * interupts, so don't use PCIMT_INT_ACKNOWLEDGE ...
+		 * interrupts, so don't use PCIMT_INT_ACKNOWLEDGE ...
 		 */
 		irq = i8259_irq();
 		if (unlikely(irq < 0))