wifi: mwifiex: add extra delay for firmware ready

For SDIO IW416, due to a bug, FW may return ready before complete full
initialization. Command timeout may occur at driver load after reboot.
Workaround by adding 100ms delay at checking FW status.

Signed-off-by: David Lin <yu-hao.lin@nxp.com>
Cc: stable@vger.kernel.org
Reviewed-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Acked-by: Brian Norris <briannorris@chromium.org>
Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com> # Verdin AM62 (IW416)
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20231208234029.2197-1-yu-hao.lin@nxp.com