clk: cdce925: check return value of kasprintf()

clk: cdce925: check return value of kasprintf()

kasprintf() returns a pointer to dynamically allocated memory.
Pointer could be NULL in case allocation fails. Check pointer validity.
Identified with coccinelle (kmerr.cocci script).

Fixes: 19fbbbbcd3a3 ("Add TI CDCE925 I2C controlled clock synthesizer driver")
Depends-on: e665f029a283 ("clk: Convert to using %pOFn instead of device_node.name")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20230530093913.1656095-3-claudiu.beznea@microchip.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>