ethernet/arc/arc_emac - fix NAPI "work > weight" warning

ethernet/arc/arc_emac - fix NAPI "work > weight" warning

Initially I improperly set a boundary for maximum number of input
packets to process on NAPI poll ("work") so it might be more than
expected amount ("weight").

This was really harmless but seeing WARN_ON_ONCE on every device boot is
not nice. So trivial fix ("<" instead of "<=") is here.

Signed-off-by: Alexey Brodkin <[email protected]>
Cc: Vineet Gupta <[email protected]>
Cc: Mischa Jonker <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Grant Likely <[email protected]>
Cc: Rob Herring <[email protected]>
Cc: Paul Gortmaker <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: [email protected]
Signed-off-by: David S. Miller <[email protected]>