powerpc/64/kexec: Fix MMU cleanup on radix

Just using the hash ops won't work anymore since radix will have
NULL in there. Instead create an mmu_cleanup_all() function which
will do the right thing based on the MMU mode.

For Radix, for now I clear UPRT and the PTCR, effectively switching
back to Radix with no partition table setup.

Currently set it to NULL on BookE thought it might be a good idea
to wipe the TLB there (Scott ?)

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/mmu.h

@@ -204,6 +204,10 @@ extern unsigned int __start___mmu_ftr_fixup, __stop___mmu_ftr_fixup;
  * make it match the size our of bolted TLB area
  */
 extern u64 ppc64_rma_size;
+
+/* Cleanup function used by kexec */
+extern void mmu_cleanup_all(void);
+extern void radix__mmu_cleanup_all(void);
 #endif /* CONFIG_PPC64 */
 
 struct mm_struct;