wifi: ath5k: fix repeated words in comments

Delete the redundant word 'don't' and 'but'.

Signed-off-by: Jilin Yuan <yuanjilin@cdjrlc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20220708154929.19199-1-yuanjilin@cdjrlc.com