power: smb1398: Fix SOC based SMB enable condition

The existing logic allows SMB's to enable even if the
SOC is above the cutoff-threshold. Fix it by negating
this logic.

Change-Id: I294874754e79557f12b76c383a6e79d90008acc5
Signed-off-by: Ashish Chavan <ashichav@codeaurora.org>