x86 smpboot_32.c section fixes

CONFIG_HOTPLUG_CPU=y:

WARNING: vmlinux.o(.text+0x22c60): Section mismatch: reference to .init.data:cpu_idle_tasks (between 'do_boot_cpu' and 'do_warm_boot_cpu')
WARNING: vmlinux.o(.text+0x22c99): Section mismatch: reference to .init.data:cpu_idle_tasks (between 'do_boot_cpu' and 'do_warm_boot_cpu')
WARNING: vmlinux.o(.text+0x2359b): Section mismatch: reference to .init.data:smp_b_stepping (between 'smp_store_cpu_info' and 'cpu_exit_clear')
WARNING: vmlinux.o(.text+0x235a0): Section mismatch: reference to .init.data:smp_b_stepping (between 'smp_store_cpu_info' and 'cpu_exit_clear')

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>