i2c: k1: Initialize variable before use

Commit 95a8ca229032 ("i2c: spacemit: add support for SpacemiT K1
SoC") introduced a check in the probe function to warn the user
if the DTS has incorrect frequency settings. In such cases, the
driver falls back to default values.

However, the return value of of_property_read_u32() was not
stored, making the check ineffective. Fix this by storing the
return value in 'ret' and evaluating it properly.

Reported-by: kernel test robot <[e-mail]>
Closes: https://lore.kernel.org/oe-kbuild-all/[e-mail]/
Cc: Troy Mitchell <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Andi Shyti <[e-mail]>

drivers/i2c/busses/i2c-k1.c

···
 	if (!i2c)
 		return -ENOMEM;
 
-	of_property_read_u32(of_node, "clock-frequency", &i2c->clock_freq);
+	ret = of_property_read_u32(of_node, "clock-frequency", &i2c->clock_freq);
 	if (ret && ret != -EINVAL)
 		dev_warn(dev, "failed to read clock-frequency property: %d\n", ret);