i386: make 'hv-spinlocks' a regular uint32 property

i386: make 'hv-spinlocks' a regular uint32 property

X86CPU.hv-spinlocks is a uint32 property that has a special setter
validating the value to be no less than 0xFFF and no bigger than
UINT_MAX.  The latter check is redundant; as for the former, there
appears to be no reason to prohibit the user from setting it to a lower
value.

So nuke the dedicated getter/setter pair and convert 'hv-spinlocks' to a
regular uint32 property.

Signed-off-by: Roman Kagan <rkagan@virtuozzo.com>
Message-Id: <20190618110659.14744-1-rkagan@virtuozzo.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>