rtw88: coex: remove unnecessary variable and label

In some funciton, the variable ret just used as return value,and
out label just return ret,so ret and out label are unnecessary,
we should delete these and use return true/false to replace.

Signed-off-by: wengjianfeng <wengjianfeng@yulong.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210520005545.31272-1-samirweng1979@163.com