powerpc/64: Export pgtable_cache and pgtable_cache_add for KVM

This exports the pgtable_cache array and the pgtable_cache_add
function so that HV KVM can use them for allocating radix page
tables for guests.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
1 file changed