mtd: gpmi: do not set the default values for the extra clocks

The default frequencies of the extra clocks are 200MHz.
The current code sets the extra clocks to 44.5MHz.

When i add the EDO feature to gpmi, i have to revert the extra clocks
to 200MHz.

So it is better that we do not set the default values for the extra
clocks. The driver runs well even when we do not set the default values for
extra clocks.

Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>