sched/balancing: Rename update_blocked_averages() => sched_balance_update_blocked_averages()

Standardize scheduler load-balancing function names on the
sched_balance_() prefix.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Link: https://lore.kernel.org/r/20240308111819.1101550-10-mingo@kernel.org