hw: Replace global smp variables with MachineState for all remaining archs

The global smp variables in alpha/hppa/mips/openrisc/sparc*/xtensa codes
are replaced with smp properties from MachineState.

A local variable of the same name would be introduced in the declaration
phase if it's used widely in the context OR replace it on the spot if it's
only used once. No semantic changes.

Signed-off-by: Like Xu <like.xu@linux.intel.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20190518205428.90532-10-like.xu@linux.intel.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>