clk: at91: pmc: do not continue if compatible not located

pmc_register_ops() is called for all AT91 devices. Return
-ENODEV in case of_find_matching_node() returns NULL.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lkml.kernel.org/r/1588508289-10140-1-git-send-email-claudiu.beznea@microchip.com


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