oplus.config: Disable CONFIG_LRU_GEN

Users were noticing random hangs on oplus sm8250 on lineage-23.0,
usually after having launched a bunch of apps over time.

We are not sure why zygote seems to end up having issues that results in
these hangs, but disabling CONFIG_LRU_GEN seems to mitigate said issues.

If you have a significant number of apps installed, you can reproduce
this issue (without this change) on your own device by running the
following shell script LuK1337 made, which will kill and re-launch every
single launchable app on your device in an infinite loop:
```
packages=()

for package in `pm list packages`; do
    package="$(echo $package | cut -b9-)"
    activity="$(cmd package resolve-activity -a android.intent.action.MAIN -c android.intent.category.LAUNCHER $package)"

    if [ "$activity" != "No activity found" ]; then
        packages+=("$package")
    fi
done

while true; do
    for package in "${packages[@]}"; do
        killall -9 $package
        am start $package
    done
done
```

Eventually, you will see the `am start` command hang suddenly, and soon,
you'll see the GUI either slow to a crawl or freeze entirely on your
phone. Depending on the number of apps you have installed, it can take
up to a few minutes for this to happen. The more apps you have
installed, the less time it takes to trigger this issue.

Co-authored-by: LuK1337 <priv.luk@gmail.com>
Fixes: https://gitlab.com/LineageOS/issues/android/-/issues/9475
Change-Id: Id395760dec59d66afe999123dc3b6f3c572c3bde

arch/arm64/configs/vendor/oplus.config

@@ -18,7 +18,6 @@ CONFIG_IFB=y
 CONFIG_IST_DOWN=y
 CONFIG_IST_UP=y
 CONFIG_KPROBES=y
-CONFIG_LRU_GEN=y
 CONFIG_MXM_DOWN=y
 CONFIG_MXM_UP=y
 CONFIG_NLS_UTF8=y