Move X86_32 only get_segment_eip to X86_64
Move X86_64 only is_errata93 to X86_32

Change X86_32 loop in is_prefetch to highlight the differences
between them.  Fold the logic from __is_prefetch in as well on
X86_32.
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>