tclap: generate empty package to address dependency requirement

JIRA: SB-3075
* Note that we encounter tclap (which is missing) required by
tclap-dev when we try to bake create-ade with fsl-networking
layer included. This PR fixes this by allowing creation of empty
package.

Signed-off-by: Fahad Arslan <Fahad_Arslan@mentor.com>