clk: ti: dra7-atl: Provide error check for incoming parameters in set_rate

commit 20411dad upstream.

Check for valid parameters in check rate. Else, we end up getting
errors.

This occurs as part of the inital clock tree update of child clock
nodes where new_rate could be 0 for non functional clocks.

Fixes: 9ac33b0c (" CLK: TI: Driver for DRA7 ATL (Audio Tracking Logic)")
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>