sparc64: Add ability to set the mcde state for a process

sparc64: Add ability to set the mcde state for a process

turn off version checking (PSTATE.mcde) to avoid tripping over ADI
versions in flux.  This has been partially remedied by using non-faulting
loads.

However, there is still a need to turn off PSTATE.mcde in memory dump
functions.  This is to determine if an address is readable.  If the
address is unreadable, the dump shows the memory contents as "********"
instead of a 4-byte hex value.

Orabug: 25130002

Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
Signed-off-by: Allen Pais <allen.pais@oracle.com>