[PARISC] fix section mismatch in smp.c

WARNING: arch/parisc/kernel/built-in.o(.text.__cpu_up+0x20): Section mismatch: reference to .init.text:smp_boot_one_cpu (after '__cpu_up')

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>