drm/hisilicon/hibmc: Replace module initialization with DRM helpers

Replace module_pci_driver() with drm_module_pci_driver(). The DRM macro
respects drm_firmware_drivers_only() and fails if the flag has been set.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211222082831.196562-6-javierm@redhat.com