staging: bcm2835: Remove dead code related to framerate.

Fixes a compiler warning about a set-but-not-used variable. I think
this was just leftover dead code from before set_framerate_params(),
since that also sets up some mmal_parameter_rational structs for fps.

Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>