drivers: gpio: pca series: dereference pointer in assignment

Properly dereference the value pointer in assignment.

```
In function 'gpio_pca_series_port_read_standard':
warning: assignment to 'gpio_port_value_t *' {aka 'unsigned int *'} \
  from 'uint32_t' {aka 'unsigned int'} makes pointer from integer   \
  without a cast [-Wint-conversion]
 1071 |                 value = sys_le32_to_cpu(input_data);
      |                       ^
```

Signed-off-by: Chris Friedt <cfriedt@tenstorrent.com>