dm: treewide: Rename 'platdata' variables to just 'plat'

We use 'priv' for private data but often use 'platdata' for platform data.
We can't really use 'pdata' since that is ambiguous (it could mean private
or platform data).

Rename some of the latter variables to end with 'plat' for consistency.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/lib/acpi/acpi_device.c b/lib/acpi/acpi_device.c
index c3439a5..52b21ce 100644
--- a/lib/acpi/acpi_device.c
+++ b/lib/acpi/acpi_device.c
@@ -602,7 +602,7 @@
 static int acpi_device_set_i2c(const struct udevice *dev, struct acpi_i2c *i2c,
 			       const char *scope)
 {
-	struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
+	struct dm_i2c_chip *chip = dev_get_parent_plat(dev);
 	struct udevice *bus = dev_get_parent(dev);
 
 	memset(i2c, '\0', sizeof(*i2c));
@@ -727,7 +727,7 @@
 	struct dm_spi_slave_platdata *plat;
 	struct spi_slave *slave = dev_get_parent_priv(dev);
 
-	plat = dev_get_parent_platdata(slave->dev);
+	plat = dev_get_parent_plat(slave->dev);
 	memset(spi, '\0', sizeof(*spi));
 	spi->device_select = plat->cs;
 	spi->device_select_polarity = SPI_POLARITY_LOW;