typo fix in comment

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/math.c b/shell/math.c
index e7565eb..006221b 100644
--- a/shell/math.c
+++ b/shell/math.c
@@ -423,7 +423,7 @@
 			 * MAX_NEGATIVE_INT / -1 = MAX_POSITIVE_INT+1
 			 * and thus is not representable.
 			 * Some CPUs segfault trying such op.
-			 * Others overfolw MAX_POSITIVE_INT+1 to
+			 * Others overflow MAX_POSITIVE_INT+1 to
 			 * MAX_NEGATIVE_INT (0x7fff+1 = 0x8000).
 			 * Make sure to at least not SEGV here:
 			 */