x86/mm: Remove unnecessary include of <linux/extable.h>

The header file linux/extable.h is included for
search_exception_tables(). That function is no longer used since commit:

  c2508ec ("mm: introduce new 'lock_mm_and_find_vma()' page fault helper")

Remove it.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20241220084029.473617-1-bigeasy@linutronix.de

Author: Sebastian Andrzej Siewior

arch/x86/mm/fault.c

@@ -7,7 +7,6 @@
 #include <linux/sched.h>		/* test_thread_flag(), ...	*/
 #include <linux/sched/task_stack.h>	/* task_stack_*(), ...		*/
 #include <linux/kdebug.h>		/* oops_begin/end, ...		*/
-#include <linux/extable.h>		/* search_exception_tables	*/
 #include <linux/memblock.h>		/* max_low_pfn			*/
 #include <linux/kfence.h>		/* kfence_handle_page_fault	*/
 #include <linux/kprobes.h>		/* NOKPROBE_SYMBOL, ...		*/