ppc/xive2: Support TIMA "Pull OS Context to Odd Thread Reporting Line"

ppc/xive2: Support TIMA "Pull OS Context to Odd Thread Reporting Line"

Adds support for single byte writes to offset 0xC18 of the TIMA address
space.  When this offset is written to, the hardware disables the OS
context and copies the current state information to the odd cache line
of the pair specified by the NVT structure indexed by the OS CAM entry.

Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Michael Kowal <kowal@linux.vnet.ibm.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>