msm: kgsl: Remove io_fraction as it is no longer used

io_fraction was originally used as a way to influence the CPU
frequency governor.  Due to governor updates and timing changes
no targets use io_fraction now and there is no plan to do so in
the future.

Signed-off-by: Lucille Sylvester <lsylvest@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>