Update Buildroot rootfs, added modprobe

Update the prebuilt of rootfs.ext4 used in QEMU environment. It was
rebuilt with kmod and kmod_tools included in the image, thus now having
/sbin/modprobe needed by kselftests.

Bug: 193407077
Test: make test
Change-Id: Ie16bce7a97aff59903df6d50149a10fbaf78afdf
diff --git a/linux-aarch64/images/rootfs.ext4 b/linux-aarch64/images/rootfs.ext4
index 4d455cb..e4930bc 100644
--- a/linux-aarch64/images/rootfs.ext4
+++ b/linux-aarch64/images/rootfs.ext4
Binary files differ