dm: core: use u32 instead of int for dev_read_u32_default

dev_read_u32_default is for getting a u32 from a Device Tree property
and allows to take a default value if that property is missing.

Considering it calls ofnode_read_u32_default which takes a u32 and
returns a u32, it should do the same instead of using an int, especially
considering that int size is typically architecture-specific, as opposed
to u32.

This incidentally matches all other dev_read_*_default functions (except
dev_read_s32_default which will be tackled in the next commit).

Fixes: 47a0fd3bad38 ("dm: core: Implement live tree 'read' functions")
Signed-off-by: Quentin Schulz <quentin.schulz@cherry.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/core/read.c b/drivers/core/read.c
index 55c19f3..981204b 100644
--- a/drivers/core/read.c
+++ b/drivers/core/read.c
@@ -38,8 +38,8 @@
 	return ofnode_read_u32(dev_ofnode(dev), propname, outp);
 }
 
-int dev_read_u32_default(const struct udevice *dev, const char *propname,
-			 int def)
+u32 dev_read_u32_default(const struct udevice *dev, const char *propname,
+			 u32 def)
 {
 	return ofnode_read_u32_default(dev_ofnode(dev), propname, def);
 }