MIPS: Fix HOTPLUG_PARALLEL dependency

With MIPS, it is possible to have SMP enabled without HOTPLUG_CPU
selected. However, in kernel/cpu.c, some code that uses
HOTPLUG_PARALLEL also requires HOTPLUG_CPU to be selected. Therefore,
we should fix the HOTPLUG_PARALLEL dependency to depend on
HOTPLUG_CPU, not just SMP.

Reported-by: kernel test robot <[e-mail]>
Closes: https://lore.kernel.org/oe-kbuild-all/[e-mail]/
Signed-off-by: Gregory CLEMENT <[e-mail]>
Signed-off-by: Thomas Bogendoerfer <[e-mail]>

arch/mips/Kconfig

···
 	select USB_UHCI_BIG_ENDIAN_DESC if CPU_BIG_ENDIAN
 	select USB_UHCI_BIG_ENDIAN_MMIO if CPU_BIG_ENDIAN
 	select USE_OF
-	select HOTPLUG_PARALLEL if SMP
+	select HOTPLUG_PARALLEL if HOTPLUG_CPU
 	help
 	  Select this to build a kernel supporting EyeQ SoC from Mobileye.