ACPI: button: Refactor lid_init_state module parsing code

Replace the weird strncmp() calls in param_set_lid_init_state(),
which look to me like they will also accept things like "opennnn"
to use sysfs_match_string instead.

Also rewrite param_get_lid_init_state() using the new lid_init_state_str
array. Instead of doing a straightforward one line replacement, e.g. :
  return sprintf(buffer, lid_init_state_str[lid_init_state]);
print all possible values, putting [] around the selected value, so
that users can easily find out what the possible values are.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>