An FPGA manager should not be required to provide a
write_sg function. Move the op check to the wrapper.
Default to -EOPNOTSUP so its users will fail
gracefully.
[mdf@kernel.org: Reworded first line]
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Moritz Fischer <mdf@kernel.org>
        return 0;
 }
 
+static inline int fpga_mgr_write_sg(struct fpga_manager *mgr,
+                                   struct sg_table *sgt)
+{
+       if (mgr->mops->write_sg)
+               return  mgr->mops->write_sg(mgr, sgt);
+       return -EOPNOTSUPP;
+}
+
 /**
  * fpga_image_info_alloc - Allocate an FPGA image info struct
  * @dev: owning device
        /* Write the FPGA image to the FPGA. */
        mgr->state = FPGA_MGR_STATE_WRITE;
        if (mgr->mops->write_sg) {
-               ret = mgr->mops->write_sg(mgr, sgt);
+               ret = fpga_mgr_write_sg(mgr, sgt);
        } else {
                struct sg_mapping_iter miter;