ACPI: Separate device_nvs_t

Remove typedef device_nvs_t and move struct device_nvs
outside of global_nvs. Also remove padding and the reserve
for chromeos_acpi_t.

Change-Id: I878746b1f0f9152a27dc58e373d58115e2dff22c
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/49476
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>

src/include/acpi/acpi_gnvs.h

@@ -8,6 +8,7 @@
 void acpi_create_gnvs(void);
 #if CONFIG(ACPI_SOC_NVS)
 void *acpi_get_gnvs(void);
+void *acpi_get_device_nvs(void);
 #else
 static inline void *acpi_get_gnvs(void) { return NULL; }
 #endif