ath10k: spelling and miscellaneous neatening

Correct some trivial comment typos.
Remove unnecessary parentheses in a long line.

Signed-off-by: Joe Perches <joe@perches.com>
[kvalo@qca.qualcomm.com: drop the change for return]
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>