clk: fractional-divider: Show numerator and denominator in debugfs

It's very useful to see what are the values of the fractional divider.
For that, add respective debugfs files.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20221122130732.48537-2-andriy.shevchenko@linux.intel.com


Signed-off-by: Stephen Boyd <sboyd@kernel.org>