configs: Make vega10_kvm.py runnable
configs: Make vega10_kvm.py runnable

The current script is echoing the command instead of running it (oops).
Also change the dmesg level to 3 to hide warnings from console output.
Level 8 should really only be used when debugging.

Change-Id: I90937ef13bf598cef1f58af69da1fdc9038d1e37
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/59052
Reviewed-by: Jason Lowe-Power <92de577f37050ad05b60626d2f17913f40dcb1a2@gmail.com>
Maintainer: Jason Lowe-Power <92de577f37050ad05b60626d2f17913f40dcb1a2@gmail.com>
Reviewed-by: Matt Sinclair <d2406197fb1bedd1e23c70c50c510ff0e9ab0f5b@gmail.com>
Maintainer: Matt Sinclair <d2406197fb1bedd1e23c70c50c510ff0e9ab0f5b@gmail.com>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>

gem5/gem5,gem5/gem5,gem5/gem5,gem5/gem5,gem5/gem5,gem5/gem5,gem5/gem5