rtlwifi: rtl8723be: Fix loss of signal

In commit c713fb07 ("rtlwifi: rtl8821ae: Fix connection lost problem
correctly") a problem in rtl8821ae that caused loss of signal was fixed.
That same problem has now been reported for rtl8723be. Accordingly,
the ASPM L1 latency has been increased from 0 to 7 to fix the instability.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Stable <stable@vger.kernel.org>
Tested-by: James Cameron <quozl@laptop.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>