On SDIO chips the firmware log does not impact performance. To make it
easier to debug firmware problems keep it enabled on the firmware.

Tested with QCA6174 SDIO with firmware WLAN.RMH.4.4.1-00029.
Signed-off-by: Wen Gong <wgong@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>