net/ice/base: add capability list AQ function

net/ice/base: add capability list AQ function

The current implementation for reading device and function capabilities
from firmware, ice_aq_discover_caps, has potentially undesirable
side effects.

ice_aq_discover_caps calls ice_parse_caps, resulting in overwriting the
capabilities stored in the hw structure. This is ok during
initialization, but means that code which wants to read the capabilities
after initialization cannot use ice_aq_discover_caps without being
careful of the side effects.

Factor out the AQ command logic into a new ice_aq_list_caps function.
This will be used by the ice_aq_discover_caps function.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Paul M Stillwell Jr <paul.m.stillwell.jr@intel.com>
Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
Acked-by: Qiming Yang <qiming.yang@intel.com>