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/board/cavium/thunderx/thunderx.c b/board/cavium/thunderx/thunderx.c
index f8c2913..b8f060b 100644
--- a/board/cavium/thunderx/thunderx.c
+++ b/board/cavium/thunderx/thunderx.c
@@ -27,7 +27,7 @@
 
 U_BOOT_DEVICE(thunderx_serial0) = {
 	.name = "serial_pl01x",
-	.platdata = &serial0,
+	.plat = &serial0,
 };
 
 static const struct pl01x_serial_platdata serial1 = {
@@ -39,7 +39,7 @@
 
 U_BOOT_DEVICE(thunderx_serial1) = {
 	.name = "serial_pl01x",
-	.platdata = &serial1,
+	.plat = &serial1,
 };
 #endif