lib: remove "expecting prototype" kernel-doc warnings

Fix various kernel-doc warnings in lib/ due to missing or erroneous
function names.

Add kernel-doc for some function parameters that was missing.  Use
kernel-doc "Return:" notation in earlycpio.c.

Quietens the following warnings:

  lib/earlycpio.c:61: warning: expecting prototype for cpio_data find_cpio_data(). Prototype was for find_cpio_data() instead

  lib/lru_cache.c:640: warning: expecting prototype for lc_dump(). Prototype was for lc_seq_dump_details() instead
  lru_cache.c:90: warning: Function parameter or member 'cache' not described in 'lc_create'

  lib/parman.c:368: warning: expecting prototype for parman_item_del(). Prototype was for parman_item_remove() instead
  parman.c:309: warning: Excess function parameter 'prority' description in 'parman_prio_init'

  lib/radix-tree.c:703: warning: expecting prototype for __radix_tree_insert(). Prototype was for radix_tree_insert() instead
  radix-tree.c:180: warning: Excess function parameter '...