wifi: rtw89: unify use of rtw89_h2c_tx()

Seaprate calling of rtw89_h2c_tx() out of if-expression, and bypass the
return value to upper caller.
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220914035034.14521-2-pkshih@realtek.com