Revert "xen/x86: Workaround 'x86/ioapic: Add register level checks to detect bogus io-apic entries'"

This reverts commit 2531d64b6fe2724dc432b67d8dc66bd45621da0b.

The two patches:
      x86/apic: Replace io_apic_ops with x86_io_apic_ops.
      xen/x86: Implement x86_apic_ops

take care of fixing it properly.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

arch/x86/xen/mmu.c

@@ -1859,7 +1859,6 @@ pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd,
 #endif	/* CONFIG_X86_64 */
 
 static unsigned char dummy_mapping[PAGE_SIZE] __page_aligned_bss;
-static unsigned char fake_ioapic_mapping[PAGE_SIZE] __page_aligned_bss;
 
 static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
 {
@@ -1900,7 +1899,7 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
 		 * We just don't map the IO APIC - all access is via
 		 * hypercalls.  Keep the address in the pte for reference.
 		 */
-		pte = pfn_pte(PFN_DOWN(__pa(fake_ioapic_mapping)), PAGE_KERNEL);
+		pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
 		break;
 #endif
 
@@ -2065,7 +2064,6 @@ void __init xen_init_mmu_ops(void)
 	pv_mmu_ops = xen_mmu_ops;
 
 	memset(dummy_mapping, 0xff, PAGE_SIZE);
-	memset(fake_ioapic_mapping, 0xfd, PAGE_SIZE);
 }
 
 /* Protected by xen_reservation_lock. */