spelling fixes: arch/sh/

Spelling fixes in arch/sh/.

Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/math-emu/math.c b/arch/sh/math-emu/math.c
index 1efbac1..a38e1ee 100644
--- a/arch/sh/math-emu/math.c
+++ b/arch/sh/math-emu/math.c
@@ -148,7 +148,7 @@
 	return 0;
 }
 
-// to process fmov's extention (odd n for DR access XD).
+// to process fmov's extension (odd n for DR access XD).
 #define FMOV_EXT(x) if(x&1) x+=16-1
 
 static int