stm32: stm32f4: move flash driver to mtd driver location

Same flash driver can be used by other stm32 families like stm32f7.
Better place for this driver would be mtd driver location.

Signed-off-by: Vikas Manocha <vikas.manocha@st.com>
diff --git a/include/flash.h b/include/flash.h
index f53ace7..c6321a0 100644
--- a/include/flash.h
+++ b/include/flash.h
@@ -465,7 +465,7 @@
 #define FLASH_S29GL064M 0x00F0		/* Spansion S29GL064M-R6		*/
 #define FLASH_S29GL128N 0x00F1		/* Spansion S29GL128N			*/
 
-#define FLASH_STM32F4	0x00F2		/* STM32F4 Embedded Flash */
+#define FLASH_STM32	0x00F2		/* STM32 Embedded Flash */
 #define FLASH_STM32F1	0x00F3		/* STM32F1 Embedded Flash */
 
 #define FLASH_UNKNOWN	0xFFFF		/* unknown flash type			*/