sched: Remove unused update_shares_locked()

Commit f492e12e ("sched: Remove
load_balance_newidle()") removed the only user of this function,
so remove it too.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1265019219.24455.128.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>