project-lakitu: Enable CONFIG_KALLSYMS kernel flag for the ARM64 dump capture kernel

Saving vmcore to disk fails with error:

```
kdump_helper[192]: Saving vmcore to /var/kdump-201806221112.
kdump_helper[192]: get_stext_symbol: (/proc/kallsyms) does not exist, will not be able to read symbols. No such file or directory
kdump_helper[192]: get_versiondep_info_arm64: Can't get the symbol of _stext.
kdump_helper[192]: calculate_plat_config: PAGE SIZE 0x1000 and VA Bits 0 not supported
kdump_helper[192]: get_machdep_info_arm64: Can't determine platform config values
kdump_helper[192]: makedumpfile Failed.
[FAILED] Failed to start Kernel crash dump saving service.
```

This happens because the CONFIG_KALLSYMS flag should be set to be able to load all the debug symbols for debugging.

BUG=b/181676788
TEST=Trigger Kernel crash
RELEASE_NOTE=Set kernel config flag to enable dump capture kernel for
ARM64

Change-Id: I1216c81acf6fb9b6f1cc030c60337bb4462d0678
Reviewed-on: https://cos-review.googlesource.com/c/cos/overlays/board-overlays/+/16890
Reviewed-by: Oleksandr Tymoshenko <ovt@google.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
2 files changed