libxc/save: remove bitmap param from send_some_pages

libxc/save: remove bitmap param from send_some_pages

In last patch we added dirty bitmap to the save context,
we no longer need to pass this param to send_some_pages.
We can get dirty bitmap from the save context.
'entries' should stay as it is a useful sanity check.

Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>