fmc: stm32_fmc2_nand: Add FMC2 driver support

Add fmc2_nand driver support. The driver implements
only read interface for NAND devices.

Change-Id: I3cd037e8ff645ce0d217092b96f33ef41cb7a522
Signed-off-by: Lionel Debieve <lionel.debieve@st.com>
Signed-off-by: Christophe Kerello <christophe.kerello@st.com>

include/drivers/st/stm32_fmc2_nand.h

+/*
+ * Copyright (c) 2019, STMicroelectronics - All Rights Reserved
+ *
+ * SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
+ */
+
+#ifndef STM32_FMC2_NAND_H
+#define STM32_FMC2_NAND_H
+
+int stm32_fmc2_init(void);
+
+#endif /* STM32_FMC2_NAND_H */