rtlwifi: rtl8192ce: Fix loss of receive performance

Driver rtl8192ce when used with the RTL8188CE device would start at about
20 Mbps on a 54 Mbps connection, but quickly drop to 1 Mbps. One of the
symptoms is that the AP would need to retransmit each packet 4 of 5 times
before the driver would acknowledge it. Recovery is possible only by
unloading and reloading the driver. This problem was reported at
https://bugzilla.redhat.com/show_bug.cgi?id=770207

.

The problem is due to a missing update of the gain setting.

Signed-off-by: Jingjun Wu <jingjun_wu@realsil.com.cn>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Stable <stable@vger.kernel.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>