qmp: Ensure consistent granularity type

qmp: Ensure consistent granularity type

We treat this field with a variety of different types everywhere
in the code. Now it's just uint32_t.

Signed-off-by: John Snow <[email protected]>
Reviewed-by: Eric Blake <[email protected]>
Reviewed-by: Max Reitz <[email protected]>
Reviewed-by: Stefan Hajnoczi <[email protected]>
Message-id: 1429314609[email protected]
Signed-off-by: Stefan Hajnoczi <[email protected]>
Signed-off-by: Kevin Wolf <[email protected]>