s390/entry: Pass the asce as parameter to sie64a()

Pass the guest ASCE explicitly as parameter, instead of having sie64a()
take it from lowcore.

This removes hidden state from lowcore, and makes things look cleaner.

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
Link: https://lore.kernel.org/r/20240703155900.103783-2-imbrenda@linux.ibm.com


Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>