lowmemorykiller: adapt from Samsung's JF series kernel - credits to faux123 https://github.com/faux123/Find5-Kernel-Source/commit/9fb3fbe09bded21869d62176201767bcde4d8887
lowmemorykiller: Add config option to support oom_adj values
The conversion to use oom_score_adj instead of the deprecated oom_adj
values breaks existing user-space code. Add a config option to convert
oom_adj values written to oom_score_adj values if they appear to be
valid oom_adj values