x86: trampoline_32.S - switch to .cpuinit.data

This patch fixes section mismatch warnings of __cpuinit
setup_trampoline() on 32-bit host.

Signed-off-by: Jacek Luczak <luczak.jacek@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>