[efi] Dump existing openers when we are unable to open a protocol

Dump the existing openers of a protocol whenever we are unable to open
a protocol using attributes of BY_DEVICE, EXCLUSIVE, or
BY_CHILD_CONTROLLER.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/drivers/net/efi/snpnet.c

 		rc = -EEFI ( efirc );
 		DBGC ( device, "SNP %p %s cannot open SNP protocol: %s\n",
 		       device, efi_handle_name ( device ), strerror ( rc ) );
+		DBGC_EFI_OPENERS ( device, device,
+				   &efi_simple_network_protocol_guid );
 		goto err_open_protocol;
 	}
 

src/interface/efi/efi_driver.c

 		       efidev->device, efi_handle_name ( efidev->device ) );
 		DBGC ( efidev->device, " %p %s: %s\n", device,
 		       efi_handle_name ( device ), strerror ( rc ) );
+		DBGC_EFI_OPENERS ( efidev->device, efidev->device,
+				   &efi_device_path_protocol_guid );
 		return rc;
 	}
 
 		DBGC ( device, "EFIDRV %p %s could not open device path: %s\n",
 		       device, efi_handle_name ( device ),
 		       strerror ( rc ) );
+		DBGC_EFI_OPENERS ( device, device,
+				   &efi_device_path_protocol_guid );
 		goto err_no_device_path;
 	}
 	efidev->path = devpath.devpath;

src/interface/efi/efi_file.c

 		rc = -EEFI ( efirc );
 		DBGC ( handle, "Could not open disk I/O protocol: %s\n",
 		       strerror ( rc ) );
+		DBGC_EFI_OPENERS ( handle, handle, &efi_disk_io_protocol_guid );
 		goto err_open;
 	}
 	assert ( diskio.diskio == &efi_disk_io_protocol );

src/interface/efi/efi_pci.c

 				  pci ) ) != 0 ) {
 		DBGC ( device, "EFIPCI %p %s could not open PCI device: %s\n",
 		       device, efi_handle_name ( device ), strerror ( rc ) );
+		DBGC_EFI_OPENERS ( device, device, &efi_pci_io_protocol_guid );
 		goto err_open;
 	}