rtlwifi: btcoexist: Convert halbtc8821a2ant.c to use standard debugging

The routines in btcoexist use different debugging routines than are used
in the other drivers. This patch converts halbtc8821a2ant.c to use the
standard routines.
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>