clk: cdce9xx: Fix use of dev_read_u32_default

clk: cdce9xx: Fix use of dev_read_u32_default

The function dev_read_u32_default does not return an error and the
variable 'val' is unsigned so testing for >= 0 will always be true. It
looks like the code was attempting to return -1 if xtal-load-pf was not
present but that cannot work. Instead use dev_read_u32 which returns an
error code separately from writing the value into the passed pointer.

This issue was found by Smatch.

Signed-off-by: Andrew Goodbody <andrew.goodbody@linaro.org>
Fixes: 260777fc2333 ("clk: cdce9xx: add support for cdce9xx clock  synthesizer")
Acked-by: Quentin Schulz <quentin.schulz@cherry.de>