The Firbolg sub-race doesn't receive an additional skill point per level as other human base race award races do. Tested with a human, firbolg, and frost half-giant character. At level 2, the human and frost half-giant barbarians received a total of 45 skill points, and a firbolg only receives 40.
All characters have 14 intelligence scores.
Human char sheet and skills at level 2:
Firbolg char sheet and skills at level 2: