drm/tegra: Fix cast to restricted __le32

Sparse warns about the following cast in the function
falcon_copy_firmware_image() ...

 drivers/gpu/drm/tegra/falcon.c:66:27: warning: cast to restricted __le32

Fix this by casting the firmware data array to __le32 instead of u32.
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/tegra/falcon.c

@@ -63,7 +63,7 @@ static void falcon_copy_firmware_image(struct falcon *falcon,
 
 	/* copy the whole thing taking into account endianness */
 	for (i = 0; i < firmware->size / sizeof(u32); i++)
-		virt[i] = le32_to_cpu(((u32 *)firmware->data)[i]);
+		virt[i] = le32_to_cpu(((__le32 *)firmware->data)[i]);
 }
 
 static int falcon_parse_firmware_image(struct falcon *falcon)