ice: Fix return value from NAPI poll

ice: Fix return value from NAPI poll

[ Upstream commit e0c9fd9b77a7334032ec407d9e14d7c3cac1ac4f ]

ice_napi_poll is hard-coded to return zero when it's done. It should
instead return the work done (if any work was done). The only time it
should return zero is if an interrupt or poll is handled and no work
is performed. So change the return value to be the minimum of work
done or budget-1.

Signed-off-by: Dave Ertman <david.m.ertman@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>