UBIFS: fix ubifs_compress commentary

Update the comment for ubifs_compress(), which incorrectly states that it
returnsa success/failure indicator.

Signed-off-by: Geert Uytterhoeven <[e-mail]>
Signed-off-by: Artem Bityutskiy <[e-mail]>

fs/ubifs/compress.c

···
  *
  * Note, if the input buffer was not compressed, it is copied to the output
  * buffer and %UBIFS_COMPR_NONE is returned in @compr_type.
- *
- * This functions returns %0 on success or a negative error code on failure.
  */
 void ubifs_compress(const void *in_buf, int in_len, void *out_buf, int *out_len,
 		    int *compr_type)