u8800: Update wifi module & config.

Changes:
 * Sync with volans.
 * Add back XO buffer controls.
 * Make sure device mode is correct without P2P enabled (after volans sync).
 * Use board provided MAC address on Huawei U8800 (after volans sync).
 * Start/Stop SME sessions without completion variables (after volans sync).
 * Add back RF settling time config (after volans sync).
 * Set low SD clock frequency.