sfc/siena: fix repeated words in comments

Delete the redundant word 'in'.

Signed-off-by: wangjianli <wangjianli@cdjrlc.com>
Link: https://lore.kernel.org/r/20220724075207.21080-1-wangjianli@cdjrlc.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>