[IA64] fix a few section mismatch warnings

Fix the following section mismatch warnings:

WARNING: vmlinux.o(.text+0x41902): Section mismatch: reference to .init.text:__alloc_bootmem (between 'ia64_mca_cpu_init' and 'ia64_do_tlb_purge')
WARNING: vmlinux.o(.text+0x49222): Section mismatch: reference to .init.text:__alloc_bootmem (between 'register_intr' and 'iosapic_register_intr')
WARNING: vmlinux.o(.text+0x62beb2): Section mismatch: reference to .init.text:__alloc_bootmem_node (between 'hubdev_init_node' and 'cnodeid_get_geoid')

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>