Input: wdt87xx_i2c - fix compiler warning

As reported by the kernel test robot, the following warning occur:

>> drivers/input/touchscreen/wdt87xx_i2c.c:1166:36: warning: 'wdt87xx_acpi_id' defined but not used [-Wunused-const-variable=]
    1166 | static const struct acpi_device_id wdt87xx_acpi_id[] = {
         |                                    ^~~~~~~~~~~~~~~

The 'wdt87xx_acpi_id' array is only used when CONFIG_ACPI is enabled.
Wrapping its definition and 'MODULE_DEVICE_TABLE' in '#ifdef CONFIG_ACPI'
prevents a compiler warning when ACPI is disabled.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202501181549.uzdlBwuN-lkp@intel.com/


Signed-off-by: Yu-Chun Lin <eleanor15x@gmail.com>
Link: https://lore.kernel.org/r/20250119084312.1851486-1-eleanor15x@gmail.com


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>