ANDROID: build.config.allmodconfig: Re-enable XFS_FS

It appears that the clang version we were using when we first introduced
build.config.allmodconfig had issues with XFS_FS, so 884416f5
("ANDROID: create build.configs for allmodconfig") made sure to disable
it.

Now that ACK uses an updated clang, attempt to re-enable that option.

Bug: 140224784
Bug: 140490203
Test: allmodconfig build for x86_64 and arm64
Fixes: 884416f5 ("ANDROID: create build.configs for allmodconfig")
Signed-off-by: Quentin Perret <qperret@google.com>
Change-Id: Iffdaaedb67162515af3b60ec62efd8f947ce17f2
Signed-off-by: Matthias Maennich <maennich@google.com>