Fixes gcc '-Wunused-but-set-variable' warning:

drivers/net/wireless/realtek/rtlwifi/btcoexist/halbtcoutsrc.c: In function 'halbtc_leave_lps':
drivers/net/wireless/realtek/rtlwifi/btcoexist/halbtcoutsrc.c:295:21: warning:
 variable 'ppsc' set but not used [-Wunused-but-set-variable]

drivers/net/wireless/realtek/rtlwifi/btcoexist/halbtcoutsrc.c: In function 'halbtc_enter_lps':
drivers/net/wireless/realtek/rtlwifi/btcoexist/halbtcoutsrc.c:318:21: warning:
 variable 'ppsc' set but not used [-Wunused-but-set-variable]

It never used since introduction in
commit aa45a673 ("rtlwifi: btcoexist: Add new mini driver")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>