Most of the code in CGX/RPM driver assumes that max lmacs per
given MAC as always, 4 and the number of MAC blocks also as 4.
With this assumption, the max number of interfaces supported is
hardcoded to 16. This creates a problem as next gen CN10KB silicon
MAC supports 8 lmacs per MAC block.
This patch solves the problem by using "max lmac per MAC block"
value from constant csrs and uses cgx_cnt_max value which is
populated based number of MAC blocks supported by silicon.