intel: Set a more useful fake devinfo->gtt_size in no-hw mode

With the old value, anv didn't think that the hardware supported 48-bit
addresses, and hit this assert:

   assert(device->supports_48bit_addresses == !device->use_relocations);

The new value of 1ull << 48 is the one reported on my Icelake machine.

Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16933>

src/intel/dev/intel_device_info.c

@@ -1894,7 +1894,8 @@ intel_get_device_info_from_fd(int fd, struct intel_device_info *devinfo)
    /* remaining initializion queries the kernel for device info */
    if (devinfo->no_hw) {
       /* Provide some sensible values for NO_HW. */
-      devinfo->gtt_size = 2ull * 1024 * 1024 * 1024;
+      devinfo->gtt_size =
+         devinfo->ver >= 8 ? (1ull << 48) : 2ull * 1024 * 1024 * 1024;
       return true;
    }