s390/dasd: Improve ERP error messages

s390/dasd: Improve ERP error messages

Some ERP errors still share the same message format and only add
different reason codes to it. These reason codes don't have any meaning
anymore.
Make the individual error messages more explicit and remove the reason
codes altogether. Comments around the error messages are also removed as
they provide no additional value anymore with more explicit messages.

Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20240209124522.3697827-2-sth@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>