rtl8723au: Remove unused configuration variables

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
rtl8723au: Remove CONFIG_FILE_FWIMG and CONFIG_EMBEDDED_FWIMG

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
rtl8723au: CONFIG_EMBEDDED_FWIMG is not defined

Remove dead code associated with this parameter.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
rtl8723au: Remove CONFIG_WIFI_TEST

This variable is never selected.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
rtl8723au: Remove undefined CONFIG_R871X_TEST

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>