serial: serial_stm32: move clock config from driver to board

This patch removes the uart clock enable from serial driver & move it in the
board code.

Signed-off-by: Vikas Manocha <vikas.manocha@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/arm/include/asm/arch-stm32f4/stm32_periph.h

@@ -0,0 +1,27 @@
+/*
+ * (C) Copyright 2016
+ * Vikas Manocha, ST Micoelectronics, vikas.manocha@st.com.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __ASM_ARM_ARCH_PERIPH_H
+#define __ASM_ARM_ARCH_PERIPH_H
+
+/*
+ * Peripherals required for pinmux configuration. List will
+ * grow with support for more devices getting added.
+ * Numbering based on interrupt table.
+ *
+ */
+enum periph_id {
+	UART1_GPIOA_9_10 = 0,
+	UART2_GPIOD_5_6,
+};
+
+enum periph_clock {
+	USART1_CLOCK_CFG = 0,
+	USART2_CLOCK_CFG,
+};
+
+#endif /* __ASM_ARM_ARCH_PERIPH_H */