enic: Use macro instead of static const variables for array sizes

In enic_ethtool.c there is no need to use static const variables to store
array sizes when a macro can be used instead.

Signed-off-by: Nelson Escobar <neescoba@cisco.com>
Signed-off-by: John Daley <johndale@cisco.com>
Signed-off-by: Satish Kharat <satishkh@cisco.com>
Link: https://patch.msgid.link/20240912005039.10797-2-neescoba@cisco.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>