rt2x00: remove duplicate word and fix typo in comment

remove duplicate word 'we' in comment
change 'then' to 'than' in comment

Signed-off-by: wengjianfeng <wengjianfeng@yulong.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210204005119.18060-1-samirweng1979@163.com