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/soc/intel/baytrail/southcluster.c

@@ -523,7 +523,6 @@ static struct device_operations device_ops = {
 	.set_resources		= pci_dev_set_resources,
 	.acpi_inject_dsdt	= southcluster_inject_dsdt,
 	.write_acpi_tables      = acpi_write_hpet,
-	.enable_resources	= NULL,
 	.init			= sc_init,
 	.enable			= southcluster_enable_dev,
 	.scan_bus		= scan_static_bus,