mb/google: Move ECFW_RW setting for non-ChromeEC boards

The boolean is stored in ChromeOS NVS, not GNVS.

Change-Id: I5c424a052d484228a456f8f0ad4fb0bed3165e09
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50877
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/include/acpi/acpi_gnvs.h

@@ -17,8 +17,6 @@ static inline void *acpi_get_gnvs(void) { return NULL; }
 static inline int acpi_reset_gnvs_for_wake(struct global_nvs **gnvs) { return -1; }
 #endif
 
-void gnvs_set_ecfw_rw(void);
-
 /*
  * These functions populate the gnvs structure in acpi table.
  * Defined as weak in common acpi as gnvs structure definition is