powerpc/mm: Use UV_WRITE_PATE ucall to register a PATE

When Ultravisor (UV) is enabled, the partition table is stored in secure
memory and can only be accessed via the UV. The Hypervisor (HV) however
maintains a copy of the partition table in normal memory to allow Nest MMU
translations to occur (for normal VMs). The HV copy includes partition
table entries (PATE)s for secure VMs which would currently be unused
(Nest MMU translations cannot access secure memory) but they would be
needed as we add functionality.

This patch adds the UV_WRITE_PATE ucall which is used to update the PATE
for a VM (both normal and secure) when Ultravisor is enabled.

Signed-off-by: Michael Anderson <andmike@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
[ cclaudio: Write the PATE in HV's table before doing that in UV's ]
Signed-off-by: Claudio Carvalho <cclaudio@linux.ibm.com>
Reviewed-by: Ryan Grimm <grimm@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190822034838.27876-5-cclaudio@linux.ibm.com