lib/list_sort: fix function type mismatches

Casting the comparison function to a different type trips indirect call
Control-Flow Integrity (CFI) checking. Remove the additional consts from
cmp_func, and the now unneeded casts.

Change-Id: Ie21cfb8bbc75632e4d96b44cf3f0c3d3331d7fa0
Fixes: 043b3f7b ("lib/list_sort: simplify and remove MAX_LIST_LENGTH_BITS")
Signed-off-by: Sami Tolvanen <samitolvanen@google.com&gt;i>
Git-commit: 5bc3f3591d783484b2e0011f3b5633c1e60e7585
Git-repo: https://github.com/samitolvanen/linux.git


Signed-off-by: Prakruthi Deepak Heragu <pheragu@codeaurora.org>