s390/fs3270: fix whitespace errors

Fix a few whitespace errors reported by checkpatch, namely
superfluous whitespace, missing spaces and empty lines.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>