rtlwifi: Fix some warnings/bugs

Some compiler/architecture combinations generate some warnings that are
not seen on my main system. Two of the "warnings" about unitialized variables
are really bugs.

Signed-off-by: Larry Finger <[e-mail]>
Signed-off-by: John W. Linville <[e-mail]>

drivers/net/wireless/rtlwifi/efuse.c

···
 
 	u8 efuse_data, word_cnts = 0;
 	u16 efuse_addr = 0;
-	u8 hworden;
+	u8 hworden = 0;
 	u8 tmpdata[8];
 
 	if (data == NULL)

drivers/net/wireless/rtlwifi/rtl8192c/fw_common.c

···
 	u16 box_reg, box_extreg;
 	u8 u1b_tmp;
 	bool isfw_read = false;
-	u8 buf_index;
+	u8 buf_index = 0;
 	bool bwrite_sucess = false;
 	u8 wait_h2c_limmit = 100;
 	u8 wait_writeh2c_limmit = 100;

drivers/net/wireless/rtlwifi/usb.c

···
 
 static void _rtl_usb_io_handler_release(struct ieee80211_hw *hw)
 {
-	struct rtl_priv *rtlpriv = rtl_priv(hw);
+	struct rtl_priv __maybe_unused *rtlpriv = rtl_priv(hw);
 
 	mutex_destroy(&rtlpriv->io.bb_mutex);
 }