Instead of calling intel_guc_init() and intel_huc_init() one by one this
patch introduces intel_uc_init_fw() function that calls them both.

Called functions are renamed accordingly.

Trying to have subject_verb_object ordering and more descriptive names,
the intel_huc_init() and intel_guc_init() functions are renamed.

For guc_init():
 * `intel_guc` is the subject, so those functions now take intel_guc
   structure, instead of the dev_priv
 * init is the verb
 * fw is the object which better describes the function's role

huc_init() change follows the same reasoning.

v2: settle on intel_uc_fetch_fw name (M. Wajdeczko)
v3: yet another rename - intel_uc_init_fw (J. Lahtinen)
v4: non-trivial rebase

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Michal Winiarski <michal.winiarski@intel.com>
Signed-off-by: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>