Configure FIMC/MFC clocks

By the hardware default, FIMC/MFC clocks are really slow.
In the hardkernel kernel on ODROID they are:

SCLK_MFC: 220MHz
SCLK_FIMCx: 176MHz
parented to MPLL.

Set the SCLK_FIMCx parents. The rate setting is then handled
by fimc-core.c.

Set the SCLK_MFC rate. On Sqwerty we run a bit slower due to
800MHz MPLL frequency.

See also: http://www.spinics.net/lists/arm-kernel/msg361197.html