We can run with any simulator clock rate.  Get rid of the code
overriding it to 6MHz.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
Patchwork: http://patchwork.linux-mips.org/patch/1669/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>