x86/viridian: Clarify some viridian logging strings

x86/viridian: Clarify some viridian logging strings

It's sadically misleading to show an error without letters and expect
the dmesg reader to understand it's in hex. The patch adds a 0x prefix
to all hex numbers that don't already have it.

On the one instance in which a boolean is printed as an integer, print
it as a decimal integer instead so it's 0/1 in the common case and not
misleading if it's ever not just that due to a bug.

While at it, rename VIRIDIAN CRASH to VIRIDIAN GUEST_CRASH. Every member
of a support team that looks at the message systematically believes
"viridian" crashed, which is absolutely not what goes on. It's the guest
asking the hypervisor for a sudden shutdown because it crashed, and
stating why.

Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
Reviewed-by: Paul Durrant <paul@xen.org>