xen/mmu: Fix compile errors introduced by x86/memblock mismerge.

The git commit d4bbf7e7
"Merge branch 'master' into x86/memblock" mismerged the 32-bit
section causing:

arch/x86/xen/mmu.c: In function ‘xen_setup_kernel_pagetable’:
arch/x86/xen/mmu.c:1855: error: expected ‘;’ before ‘)’ token
arch/x86/xen/mmu.c:1855: error: expected statement before ‘)’ token
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

arch/x86/xen/mmu.c

@@ -1852,7 +1852,7 @@ pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd,
 	xen_write_cr3(__pa(initial_page_table));
 
 	memblock_reserve(__pa(xen_start_info->pt_base),
-			 xen_start_info->nr_pt_frames * PAGE_SIZE));
+			 xen_start_info->nr_pt_frames * PAGE_SIZE);
 
 	return initial_page_table;
 }