fm10k: cleanup namespace pollution

Make functions that should be static.  While we're at it, fix the function
header comment for fm10k_tlv_attr_nest_stop(), and update the copyright
header for fm10k_pf.h, fm10k_tlv.c and fm10k_tlv.h.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Krishneil Singh <Krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>