[S390] Get rid of console setup functions.

We get this:

Section mismatch: reference to .init.text:con3270_consetup from .data
		  between 'con3270' (at offset 0x45c8) and 'con3270_fn'
Section mismatch: reference to .init.text:con3215_consetup from .data
		  between 'con3215' (at offset 0x4678) and
		  'raw3215_ccw_driver'

Since there is no difference between a non present console setup
function and one that returns only 0 remove them.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>