target-ppc: Change default machine for 64-bit

Currently, for qemu-system-ppc64, the default machine type is 'mac99'.
The mac99 machine is not being actively maintained, and represents a
bizarre hybrid of components that never actually existed as a real system.
This patch changes the default machine to 'pseries', which is actively
maintained and works well with most modern ppc64 Linux distributions as a
guest.

Because the pseries machine type is optional (it is only built when libfdt
is available), this can result in a build with no default machine.  In that
case vl.c will print a "No machine found" message.  This seems reasonable,
given that as mentioned, mac99 is unlikely to be a good choice.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
target-ppc kvm: save cr register

This adds a missing code to save CR (condition register) via
kvm_arch_put_registers(). kvm_arch_get_registers() already has it.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
pseries: Update MAINTAINERS information

I'm no longer at IBM, and therefore no long actively working on the pseries
(aka sPAPR) qemu machine type.  This patch replaces my information in the
MAINTAINERS file with that for Alexey Kardashevskiy, who is taking over
maintainership of the pseries code.  While we're at it, I've added some
extra file patterns for pseries specific files that weren't included in the
existing pattern.

Cc: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>