s390/hvc_iucv: add simple wildcard matches to the iucv allow filter

Introduce a wildcard character to filter a range of z/VM user IDs with a single
filter entry.  Only the leading portion up to the wildcard of an filter entry
contributes to the match.

This reduces the filter size and avoids configuration updates when deploying
new terminal server instances.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>