qseecom:Fix race condition while voting for clocks

In the current functionality, if DFAB clock is already on and a
request is made to turn on SFPB clock, the DFAB clock is turned
off and SFPB clock is turned on and vice-versa.

The above situation can lead to unexpected errors. The current fix
makes sure that clocks that are on are not voted to be off without
explicit request.

Change-Id: I6c3230e23b105c049cdb0aace579b8a176328c84
Signed-off-by: Ramesh Masavarapu <rameshm@codeaurora.org>