ice: Add code for DCB initialization part 1/4

This patch introduces a skeleton for ice_init_pf_dcb, the top level
function for DCB initialization. Subsequent patches will add to this
DCB init flow.

In this patch, ice_init_pf_dcb checks if DCB is a supported capability.
If so, an admin queue call to start the LLDP and DCBx in firmware is
issued. If not, an error is reported. Note that we don't fail the driver
init if DCB init fails.

Reviewed-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>