x86: function ifdefs in fault_32|64.c

Add caller of is_errata93() to X86_32, ifdef'd to do
nothing.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>