plat: imx7: refactor code for reuse

For the iMX7 SOCs, part of the code for platform
setup implementation can be reused and made
common for all these SoCs. This patch extracts
the common part for reuse.

Signed-off-by: Jun Nie <jun.nie@linaro.org>
Change-Id: I42fd4167e6903416df96a0159a046abf3896e878
diff --git a/plat/imx/imx7/include/imx7_def.h b/plat/imx/imx7/include/imx7_def.h
new file mode 100644
index 0000000..77a8ca3
--- /dev/null
+++ b/plat/imx/imx7/include/imx7_def.h
@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) 2018-2019, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef IMX7_DEF_H
+#define IMX7_DEF_H
+
+#include <stdint.h>
+
+
+/*******************************************************************************
+ * Function and variable prototypes
+ ******************************************************************************/
+void plat_imx7_io_setup(void);
+void imx7_platform_setup(u_register_t arg1, u_register_t arg2,
+			 u_register_t arg3, u_register_t arg4);
+
+#endif /*IMX7_DEF_H */