ACPI: Select ACPI_SOC_NVS only where suitable

Having some symmetry with <soc/nvs.h> now allows to reduce
the amount of gluelogic to determine the size and cbmc field
of struct global_nvs.

Since GNVS creation is now controlled by ACPI_SOC_NVS,
drivers/amd/agesa/nvs.c becomes obsolete and soc/amd/cezanne
cannot have this selected until <soc/nvs.h> exists.

Change-Id: Ia9ec853ff7f5e7908f7e8fc179ac27d0da08e19d
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/49344
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Lance Zhao

src/acpi/nvs.c

@@ -15,9 +15,13 @@ uint32_t *gnvs_cbmc_ptr(struct global_nvs *gnvs)
 }
 
 /* Some <soc/nvs.h> have no chromeos entry. */
-#if CONFIG(MAINBOARD_HAS_CHROMEOS)
 void *gnvs_chromeos_ptr(struct global_nvs *gnvs)
 {
+#if CONFIG(BOARD_EMULATION_QEMU_X86_Q35)
+	return NULL;
+#elif CONFIG(MAINBOARD_HAS_CHROMEOS)
 	return &gnvs->chromeos;
-}
+#else
+	return NULL;
 #endif
+}