xen/arm: cpuerrata: Align a virtual address before unmap

After changes introduced by 9cc0618eb0 "xen/arm: mm: Sanity check any
update of Xen page tables" we are able to vmap/vunmap page aligned
addresses only.

So if we add a page address remainder to the mapped virtual address,
we have to mask it out before unmapping.

Signed-off-by: Andrii Anisov <andrii_anisov@epam.com>
Acked-by: Julien Grall <julien.grall@arm.com>

xen/arch/arm/cpuerrata.c

@@ -75,7 +75,7 @@ static bool copy_hyp_vect_bpi(unsigned int slot, const char *hyp_vec_start,
     clean_dcache_va_range(dst_remapped, VECTOR_TABLE_SIZE);
     invalidate_icache();
 
-    vunmap(dst_remapped);
+    vunmap((void *)((vaddr_t)dst_remapped & PAGE_MASK));
 
     return true;
 }