dm: exynos: Tidy up GPIO headers

The wrong header is being included, thus requiring the code to re-declare
the generic GPIO interface in each GPIO header.

Fix this.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/samsung/trats/trats.c b/board/samsung/trats/trats.c
index 3dd340b..9e76b5d 100644
--- a/board/samsung/trats/trats.c
+++ b/board/samsung/trats/trats.c
@@ -10,8 +10,8 @@
 #include <common.h>
 #include <lcd.h>
 #include <asm/io.h>
+#include <asm/gpio.h>
 #include <asm/arch/cpu.h>
-#include <asm/arch/gpio.h>
 #include <asm/arch/pinmux.h>
 #include <asm/arch/clock.h>
 #include <asm/arch/mipi_dsim.h>