[ipgen] Do not copy template description file
[ipgen] Do not copy template description file

The instantiated template is not a template any more, so no template
description is necessary. Its presence actually adds to the confusion.

Signed-off-by: Philipp Wagner <5a4b10454c30419e54a1570be358a516ff84bb63@lowrisc.org>

lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan,lowRISC/opentitan