scripts/spelling.txt: fix malformed entry

One of the entries has three fields "mistake||correction||correction"
rather than the expected two fields "mistake||correction".  Fix it.

Signed-off-by: Eric Biggers <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

Author: ebiggers

scripts/spelling.txt

@@ -589,7 +589,7 @@ explictly||explicitly
 expresion||expression
 exprimental||experimental
 extened||extended
-exteneded||extended||extended
+exteneded||extended
 extensability||extensibility
 extention||extension
 extenstion||extension