powerpc/mm: Use the correct pointer when setting a 2MB pte

powerpc/mm: Use the correct pointer when setting a 2MB pte

commit a0615a16f7d0ceb5804d295203c302d496d8ee91 upstream.

When setting a 2MB pte, radix__map_kernel_page() is using the address

	ptep = (pte_t *)pudp;

Fix this conversion to use pmdp instead. Use pmdp_ptep() to do this
instead of casting the pointer.

Fixes: 2bfd65e45e87 ("powerpc/mm/radix: Add radix callbacks for early init routines")
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Reza Arbab <arbab@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>