s390/sclp: fix new line detection

When printing multi-line text using sclp_print, line endings are not
correctly handled. The routine is expecting an EBCDIC new line character
as line terminator while the input text is encoded in ASCII format.

Fix this problem by modifying sclp_print to scan for ASCII new line
characters.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>