feat(dasd): minimize dasd handling consolidated in s390-tools

Parsing of rd.dasd is handled by s390-tools zdev dracut module 95zdev as of
ibm-s390-linux/s390-tools@9927023
("zdev/dracut: add rd.dasd cmdline option handling").

Even though this removes one implementation of parsing rd.dasd in dracut,
above s390-tools change introduces another implementation of parsing the
exact same rd.dasd syntax. Therefore, it would be good to keep the
documentation in man/dracut.cmdline.7 of dracut as one central place
describing all s390 device types that dracut handles.

For the time being, keep copying /etc/dasd.conf.
The corresponding call to dasd_cio_free is in 95dasd_mod/parse-dasd-mod.sh
and indirectly triggers processing of /etc/dasd.conf even with the typical
cio_ignore kernel boot parameter ignoring most devices.

Preparation for consolidating persistent configuration with zdev.

Signed-off-by: Steffen Maier <maier@linux.ibm.com>

modules.d/95dasd/module-setup.sh

@@ -4,20 +4,18 @@
 check() {
     local _arch=${DRACUT_ARCH:-$(uname -m)}
     [ "$_arch" = "s390" -o "$_arch" = "s390x" ] || return 1
-    require_binaries normalize_dasd_arg || return 1
+    require_binaries dasdconf.sh || return 1
     return 0
 }
 
 # called by dracut
 depends() {
-    echo "dasd_mod"
     return 0
 }
 
 # called by dracut
 install() {
-    inst_hook cmdline 30 "$moddir/parse-dasd.sh"
-    inst_multiple dasdinfo dasdconf.sh normalize_dasd_arg
+    inst_multiple dasdconf.sh
     conf=/etc/dasd.conf
     if [[ $hostonly && -f $conf ]]; then
         inst -H $conf