arm64: Kconfig: Fix dependencies to enable ACPI_HOTPLUG_CPU

Both ACPI_PROCESSOR and HOTPLUG_CPU are needed by ACPI_HOTPLUG_CPU.
Otherwise, we can have compiling error with the following configurations.

  CONFIG_HOTPLUG_CPU=n
  CONFIG_ACPI_PROCESSOR=y
  CONFIG_ACPI_HOTPLUG_CPU=y

  arch/arm64/kernel/smp.c: In function ‘arch_unregister_cpu’:
  arch/arm64/kernel/smp.c:563:9: error: implicit declaration of  \
  function ‘unregister_cpu’; did you mean ‘register_cpu’?        \
  [-Werror=implicit-function-declaration]
  563 |         unregister_cpu(c);
      |         ^~~~~~~~~~~~~~
      |         register_cpu

Fix it by enabling ACPI_HOTPLUG_CPU when both ACPI_PROCESSOR and
HOTPLUG_CPU are enabled, consistent with other architectures like
x86 and loongarch.

Fixes: 9d087389 ("arm64: Kconfig: Enable hotplug CPU on arm64 if ACPI_PROCESSOR is enabled.")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202406300437.XnuW0n34-lkp@intel.com/Signed-off-by: Gavin Shan <gshan@redhat.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20240701001132.1585153-1-gshan@redhat.comSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/Kconfig

@@ -5,7 +5,7 @@ config ARM64
 	select ACPI_CCA_REQUIRED if ACPI
 	select ACPI_GENERIC_GSI if ACPI
 	select ACPI_GTDT if ACPI
-	select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR
+	select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR && HOTPLUG_CPU
 	select ACPI_IORT if ACPI
 	select ACPI_REDUCED_HARDWARE_ONLY if ACPI
 	select ACPI_MCFG if (ACPI && PCI)