rtlwifi: Fix unitialized variable warnings

In http://lkml.indiana.edu/hypermail/linux/kernel/1104.1/01955.html, Geerti
Uytterhoeven reports the following warnings for the rtlwifi drivers.

src/drivers/net/wireless/rtlwifi/rtl8192c/dm_common.c: warning:
	 'cck_index' may be used uninitialized in this function: => 637
src/drivers/net/wireless/rtlwifi/rtl8192c/dm_common.c: warning:
	 'cck_index_old' may be used uninitialized in this function: => 637
src/drivers/net/wireless/rtlwifi/rtl8192c/fw_common.c: warning:
	 'box_extreg' may be used uninitialized in this function: => 303
src/drivers/net/wireless/rtlwifi/rtl8192c/fw_common.c: warning:
	 'box_reg' may be used uninitialized in this function: => 303
src/drivers/net/wireless/rtlwifi/rtl8192ce/rf.c: warning:
	 'chnlgroup' may be used uninitialized in this function: => 205
src/drivers/net/wireless/rtlwifi/rtl8192ce/rf.c: warning:
	 'u4_regvalue' may be used uninitialized in this function: => 450
src/drivers/net/wireless/rtlwifi/rtl8192cu/hw.c: warning:
	 'hq_sele' may be used uninitialized in this function: => 924

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>