scsi: sun_esp: Use module_platform_driver to simplify the code

Use module_platform_driver() to eliminate boilerplate code.

Link: https://lore.kernel.org/r/20200914065403.3726462-1-liushixin2@huawei.com


Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>