sched: core_ctl: remove unneccesary error log

Error log gets printed only when tried to turn off boost when
it was already turned off.

Change-Id: Ia8a94a3b6f9fb0d940466b4185342b975ed58e47
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>