x86: fix smp init sections

Fix Voyager section mismatch due to using __devinit instead of __cpuinit.

WARNING: vmlinux.o(.text+0xd943): Section mismatch: reference to .init.text:init_gdt (between 'voyager_smp_prepare_boot_cpu' and 'smp_vic_cmn_interrupt')

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>