sched: debug: Print additional information in /proc/sched_debug

Provide information in /proc/sched_debug on min_capacity, max_capacity
and whether pelt or window-based task load statistics is in use.

Change-Id: Ie4e9450652f4c83110dda75be3ead8aa5bb355c3
Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>