s390/cio: clean up DEV_STATE_SENSE_PGID

Clean up DEV_STATE_SENSE_PGID related code, since it's not
used anymore. Everything related to path verification is
handled within DEV_STATE_VERIFY.

Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Acked-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>