intel_scu_ipc: calculate divisor for osc clk

intel_scu_ipc: calculate divisor for osc clk

BZ: 16972 20596

Accept requested frequency as parameter to intel_scu_ipc_osc_clk()
when a clock is enabled. The base frequency varies between
different platforms so take it into account in the calculations.

Also fix any calls to intel_scu_ipc_osc_clk() to provide the
requested frequency.

Change-Id: Id1ca4f1067e766de744543018fe5427db2de0b75
Signed-off-by: Tuukka Toivonen <tuukka.toivonen@intel.com>
Reviewed-on: http://android.intel.com:8080/32620
Reviewed-by: Koski, Anttu <anttu.koski@intel.com>
Tested-by: Koski, Anttu <anttu.koski@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>