mb/*/*/acpi_tables: Don't zero out gnvs again

The gnvs structure was zeroed out before calling acpi_create_gnvs(...)
in the following files:

* src/southbridge/intel/*/lpc.c

Change-Id: Id7755b1e4b8f5cb8abd1f411b5dc174b6beee21c
Signed-off-by: Peter Lemenkov <lemenkov@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/37956
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/emulation/qemu-q35/acpi_tables.c

@@ -28,7 +28,6 @@
 
 void acpi_create_gnvs(global_nvs_t *gnvs)
 {
-	memset((void *)gnvs, 0, sizeof(*gnvs));
 	gnvs->apic = 1;
 	gnvs->mpen = 1; /* Enable Multi Processing */