s390/qdio: inline shared_ind()

This is just prep work for a subsequent patch, no functional change.

For the non-polling path we can pull the code chunk in front of the
for-loop, since it only evaluates to true for a 1-queue configuration.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>