stm32: add support for stm32f7 & stm32f746 discovery board

This patch adds support for stm32f7 family & stm32f746 board.

Signed-off-by: Vikas Manocha <vikas.manocha@st.com>
diff --git a/board/st/stm32f746-disco/Kconfig b/board/st/stm32f746-disco/Kconfig
new file mode 100644
index 0000000..09289d2
--- /dev/null
+++ b/board/st/stm32f746-disco/Kconfig
@@ -0,0 +1,19 @@
+if TARGET_STM32F746_DISCO
+
+config SYS_BOARD
+	string
+	default "stm32f746-disco"
+
+config SYS_VENDOR
+	string
+	default "st"
+
+config SYS_SOC
+	string
+	default "stm32f7"
+
+config SYS_CONFIG_NAME
+	string
+	default "stm32f746-disco"
+
+endif