Change sysenter_setup to __cpuinit.
Change __INIT & __INITDATA to be cpu hotplug aware.

Resolve MODPOST warnings similar to:

WARNING: vmlinux - Section mismatch: reference to .init.text:sysenter_setup from
 .text between 'identify_cpu' (at offset 0xc040a380) and 'detect_ht'

and

WARNING: vmlinux - Section mismatch: reference to .init.data:vsyscall_int80_end
from .text between 'sysenter_setup' (at offset 0xc041a269) and 'enable_sep_cpu'
WARNING: vmlinux - Section mismatch: reference to
.init.data:vsyscall_int80_start from .text between 'sysenter_setup' (at offset
0xc041a26e) and 'enable_sep_cpu'
WARNING: vmlinux - Section mismatch: reference to
.init.data:vsyscall_sysenter_end from .text between 'sysenter_setup' (at offset
0xc041a275) and 'enable_sep_cpu'
WARNING: vmlinux - Section mismatch: reference to
.init.data:vsyscall_sysenter_start from .text between 'sysenter_setup' (at
offset 0xc041a27a) and 'enable_sep_cpu'
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>