ANDROID: sched/core: Remove remnants of commit fd5c98da1a42

Commit fd5c98da1a42 "WIP: sched: Store system-wide maximum cpu capacity
in root domain" was repalced by commit 8148bdfff4f5 "WIP: sched: Update
max cpu capacity in case of max frequency constraints" which didn't
remove all the now unused bits.

Change-Id: I067f6366431f43337cffa7a2a8e0de32dd33d2f9
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
(cherry picked from commit 6d284a607cec51bcafca313bc396bc3103b1e876)
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
Signed-off-by: Quentin Perret <quentin.perret@arm.com>