MAINTAINERS: wifi: rtlwifi: remove git tree

Linville's tree hasn't been used for something like 10 years so remove it.
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230828123603.87621-2-kvalo@kernel.org

MAINTAINERS

@@ -18061,7 +18061,6 @@ REALTEK WIRELESS DRIVER (rtlwifi family)
 M:	Ping-Ke Shih <pkshih@realtek.com>
 L:	linux-wireless@vger.kernel.org
 S:	Maintained
-T:	git git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-testing.git
 F:	drivers/net/wireless/realtek/rtlwifi/
 
 REALTEK WIRELESS DRIVER (rtw88)