xen/arm: gic-v3: Use vsize instead of csize for virtual CPU interface

gicv3_iomem_deny_access() incorrectly uses csize (physical CPU
interface size) instead of vsize (virtual CPU interface size) when
calculating the number of pages to deny for the virtual CPU interface
region at vbase.

Fixes: 8300b3377e ("arm/gic: Add a new callback to deny Dom0 access to GIC regions")
Signed-off-by: Michal Orzel <michal.orzel@amd.com>
Reviewed-by: Ayan Kumar Halder <ayan.kumar.halder@amd.com>
Reviewed-by: Luca Fancellu <luca.fancellu@arm.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
(cherry picked from commit 9af54b65a4)

xen/arch/arm/gic-v3.c

@@ -1492,7 +1492,7 @@ static int gicv3_iomem_deny_access(struct domain *d)
     if ( vbase != INVALID_PADDR )
     {
         mfn = vbase >> PAGE_SHIFT;
-        nr = PFN_UP(csize);
+        nr = PFN_UP(vsize);
         return iomem_deny_access(d, mfn, mfn + nr - 1);
     }