soc/amd/stoneyridge: remove superfluous NULL field initialization

By definition in C, fields that are not explicitly initialized will
be zero'd out. Therefore, remove the redundant struture field
initialization.

Change-Id: I1b3b2ddf6d2a763e65861a7bcebc6b7cd96691c2
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/22314
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>

src/soc/amd/stoneyridge/hda.c

@@ -36,8 +36,6 @@ static struct device_operations hda_audio_ops = {
 	.read_resources = pci_dev_read_resources,
 	.set_resources = pci_dev_set_resources,
 	.enable_resources = pci_dev_enable_resources,
-	.init = NULL,
-	.scan_bus = NULL,
 	.ops_pci = &lops_pci,
 };