CLEANUP: cfgparse: Fix type of second calloc() parameter

`curr_idle_thr` is of type `unsigned int`, not `int`. Fix this issue by
taking the size of the dereferenced `curr_idle_thr` array.

This issue was introduced when adding the `curr_idle_thr` struct member
in commit f131481a0af79037bc6616edf450ae81d80084d7. This commit is first
tagged in 2.0-dev1 and marked for backport to 1.9.
1 file changed