drm/panel: declare variable as __be16

Declare the temp variable as __be16 to address the following sparse
warning:
drivers/gpu/drm/panel/panel-lg-lg4573.c:45:20: warning: incorrect type in initializer (different base types)
drivers/gpu/drm/panel/panel-lg-lg4573.c:45:20:    expected unsigned short [unsigned] [usertype] temp
drivers/gpu/drm/panel/panel-lg-lg4573.c:45:20:    got restricted __be16 [usertype] <noident>
Signed-off-by: Wambui Karuga <wambui.karugax@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20191230195609.12386-1-wambui.karugax@gmail.com

drivers/gpu/drm/panel/panel-lg-lg4573.c

@@ -42,7 +42,7 @@ static int lg4573_spi_write_u16(struct lg4573 *ctx, u16 data)
 	struct spi_transfer xfer = {
 		.len = 2,
 	};
-	u16 temp = cpu_to_be16(data);
+	__be16 temp = cpu_to_be16(data);
 	struct spi_message msg;
 
 	dev_dbg(ctx->panel.dev, "writing data: %x\n", data);