dm: treewide: Rename ..._platdata variables to just ..._plat

Try to maintain some consistency between these variables by using _plat as
a suffix for them.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/spi/nxp_fspi.c b/drivers/spi/nxp_fspi.c
index 04a296a..006dd04 100644
--- a/drivers/spi/nxp_fspi.c
+++ b/drivers/spi/nxp_fspi.c
@@ -887,7 +887,7 @@
 {
 	struct nxp_fspi *f;
 	struct udevice *bus;
-	struct dm_spi_slave_platdata *slave_plat = dev_get_parent_plat(dev);
+	struct dm_spi_slave_plat *slave_plat = dev_get_parent_plat(dev);
 
 	bus = dev->parent;
 	f = dev_get_priv(bus);