ice: Suppress Coverity warnings for xdp_rxq_info_reg

Coverity reports some of the calls to xdp_rxq_info_reg() as potential
issues, because the driver does not check its return value. However,
those calls are wrapped with "if (!xdp_rxq_info_is_reg(&ring->xdp_rxq))"
and this check alone is enough to be sure that the function will never
fail.

All possible states of xdp_rxq_info are:
 - NEW,
 - REGISTERED,
 - UNREGISTERED,
 - UNUSED.

The driver won't mark a queue as UNUSED under no circumstance, so the
return value can be ignored safely.

Add comments for Coverity right above calls to xdp_rxq_info_reg() to
suppress the warnings.

Signed-off-by: Krzysztof Kazimierczak <krzysztof.kazimierczak@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>