gpio: crystalcove: add missing MODULE_ALIAS()

The crystalcove GPIO driver lacks a MODULE_ALIAS() to allow it to be
auto-loaded.

Fix this by adding the missing platform alias.

Fixes: 104fb1d5153c ("gpio: Add support for Intel Crystal Cove PMIC")
Assisted-by: LLM
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>