rtlwifi: fix places where uninitialized data is used

drivers/net/wireless/rtlwifi/rtl8192ce/trx.c: In function ‘rtl92ce_rx_query_desc’:
drivers/net/wireless/rtlwifi/rtl8192ce/trx.c:255:5: warning: ‘rf_rx_num’ may be used uninitialized in this function
drivers/net/wireless/rtlwifi/rtl8192ce/trx.c:257:12: warning: ‘total_rssi’ may be used uninitialized in this function
drivers/net/wireless/rtlwifi/rtl8192ce/trx.c:466:6: warning: ‘weighting’ may be used uninitialized in this function

This work was supported by a hardware donation from the CE Linux Forum.

Signed-off-by: Alessio Igor Bogani <abogani@kernel.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>