block: Consistently call bdrv_activate() outside coroutine

block: Consistently call bdrv_activate() outside coroutine

Migration code can call bdrv_activate() in coroutine context, whereas
other callers call it outside of coroutines. As it calls other code that
is not supposed to run in coroutines, standardise on running outside of
coroutines.

This adds a no_co_wrapper to switch to the main loop before calling
bdrv_activate().

Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230504115750.54437-3-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit da4afaff074e56b0fa0d25abf865784148018895)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>