ACPICA compilation error on x86_64_defconfig (W=1 build)

[Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>]

v6.15-rc1 (but seems older should also be problematic) fails to compile by
Clang 19 with `make W=1`.

  CC      drivers/acpi/acpica/nsaccess.o
  drivers/acpi/acpica/nsaccess.c:295:6: error: variable 'num_carats' set but not used [-Werror,-Wunused-but-set-variable]
    295 |         u32 num_carats;
        |             ^
  1 error generated.

I looked briefly in the code and I have no idea how to fix this, as probably
__maybe_unused not an option for ACPICA. Hence this report.

Note, the in-tree defconfig is in use:

	git checkout v6.15-rc1
	make x86_64_defconfig
	make W=1

should trigger it.

-- 
With Best Regards,
Andy Shevchenko