feat(nxp-clk): add a basic get_rate implementation

Replace the dummy implementation of clk_ops.get_rate with a basic
version that only handles the oscillator objects. Subsequent commits
will add more objects to this list.

Change-Id: I8c1bbbfa6b116fdcf5a1f1353bdb52b474bac831
Signed-off-by: Ghennadi Procopciuc <ghennadi.procopciuc@nxp.com>
3 files changed