ACPI: TAD: Check AC wake capability before enabling wakeup

ACPI: TAD: Check AC wake capability before enabling wakeup

ACPI_TAD_AC_WAKE is a non-zero bit definition, so testing the macro
itself is always true. As a result, every TAD device is initialized as
a system wakeup device, including RTC-only devices and devices whose
wake capability bits were cleared because _PRW is absent.

Test the capability value returned by _GCP instead. This keeps
RTC-only TAD devices usable without advertising a wakeup capability
that the firmware does not provide.

Fixes: 6c711fde3a1c ("ACPI: TAD: Support RTC without wakeup")
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Xu Rao <raoxu@uniontech.com>
Link: https://patch.msgid.link/961A84FF37B50665+20260625132903.2840457-1-raoxu@uniontech.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>