Drop explicit NULL initializations from device_operations

Unmentioned fields are initialized with 0 (or NULL) implicitly. Beside
that, the struct has grown over the years. There are too many optional
fields to list them all.

Change-Id: Icb9e14c58153d7c14817bcde148e86e977666e4b
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/40126
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/drivers/net/atl1e.c

@@ -162,7 +162,6 @@ static struct device_operations atl1e_ops  = {
 	.set_resources    = pci_dev_set_resources,
 	.enable_resources = pci_dev_enable_resources,
 	.init             = atl1e_init,
-	.scan_bus         = 0,
 };
 
 static const struct pci_driver atl1e_driver __pci_driver = {

src/drivers/net/ne2k.c

@@ -317,8 +317,6 @@ static struct device_operations ne2k_ops  = {
 	.read_resources   = read_resources,
 	.set_resources    = pci_dev_set_resources,
 	.enable_resources = pci_dev_enable_resources,
-	.init             = 0,
-	.scan_bus         = 0,
 };
 
 static const struct pci_driver ne2k_driver __pci_driver = {

src/drivers/net/r8168.c

@@ -372,7 +372,6 @@ static struct device_operations r8168_ops  = {
 	.set_resources    = pci_dev_set_resources,
 	.enable_resources = pci_dev_enable_resources,
 	.init             = r8168_init,
-	.scan_bus         = 0,
 #if CONFIG(HAVE_ACPI_TABLES)
 	.acpi_name        = r8168_net_acpi_name,
 	.acpi_fill_ssdt   = r8168_net_fill_ssdt,