os.linux: Do not define the default kernel layout in the interface

os.linux: Do not define the default kernel layout in the interface

Instead point users directry to DefaultEventLayout.

This avoids a circular reference from IKernelEventLayout layout
to one of its own implementations.

Change-Id: I3c87767df4285c18b9216209942b069fef4d34cf
Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Reviewed-on: https://git.eclipse.org/r/70080
Reviewed-by: Hudson CI
Reviewed-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Tested-by: Matthew Khouzam <matthew.khouzam@ericsson.com>