Use the module_pci_driver() macro to make the code simpler by eliminating
module_init() and module_exit() calls.

Link: https://lore.kernel.org/r/20200917071045.1909320-1-liushixin2@huawei.comSigned-off-by: Liu Shixin <liushixin2@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>