eth: fbnic: Replace firmware field macros

Replace the firmware field macros with new macros which follow typical
kernel standards. No variables are required to be predefined for use and
results are now returned. These macros are prefixed with fta or fbnic
TLV attribute.

Signed-off-by: Lee Trager <lee@trager.us>
Link: https://patch.msgid.link/20250228191935.3953712-4-lee@trager.us


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