clk: Fix clk_set_parent() regression

clk: Fix clk_set_parent() regression

The commit ac30d90f3367 ("clk: Ensure the parent clocks are enabled
while reparenting") add a call to clk_enable() for the parent clock.

For clock drivers that do not implement the enable() ops, like most
Rockchip clock drivers, this now cause the set_parent() ops to never
be called when CLK_CCF=n (default for Rockchip).

clk_enable() typically return -ENOSYS when the enable() ops is not
implemented by the clock driver, with CLK_CCF=y clk_enable() instead
return 0 when the enable() ops is unimplemented.

Change to ignore -ENOSYS from the newly introduced clk_enable() call to
fix this regression and restore the old behavior of set_parent() ops
being called regardless of if enable() ops is implemented or not.

Fixes: ac30d90f3367 ("clk: Ensure the parent clocks are enabled while reparenting")
Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Tested-by: Dang Huynh <danct12@riseup.net>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>