ice: split ice_parse_caps into separate functions

The ice_parse_caps function is used to convert the capability block data
coming from firmware into a structured format used by other parts of the
code.

The current implementation directly updates the hw->func_caps and
hw->dev_caps structures. It is directly called from within
ice_aq_discover_caps. This causes the discover_caps function to have the
side effect of modifying the HW capability structures, which is not
intuitive.

Split this function into ice_parse_dev_caps and ice_parse_func_caps.
These functions will take a pointer to the dev_caps and func_caps
respectively. Also create an ice_parse_common_caps for sharing the
capability logic that is common to device and function.

Doing so enables a future refactor to allow reading and parsing
capabilities into a local caps structure instead of modifying the
members of the HW structure directly.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>