nfp: split reading capabilities out of nfp_net_init()
nfp_net_init() is a little long and we are about to add more
code to reading capabilties. Move the capability reading,
parsing and validating out. Only actual initialization
will stay in nfp_net_init().
No functional changes.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>