board: atmel: sam9x60ek: add SYS_MALLOC_F_LEN to SYS_INIT_SP_ADDR

Heap base address is computed based on SYS_INIT_SP_ADDR by
subtracting the SYS_MALLOC_F_LEN value in
board_init_f_init_reserve().
Signed-off-by: NClaudiu Beznea <claudiu.beznea@microchip.com>

include/configs/sam9x60ek.h

@@ -40,7 +40,8 @@
 #define CONFIG_SYS_SDRAM_SIZE		0x10000000	/* 256 megs */
 
 #define CONFIG_SYS_INIT_SP_ADDR \
-	(CONFIG_SYS_SDRAM_BASE + 16 * 1024 - GENERATED_GBL_DATA_SIZE)
+	(CONFIG_SYS_SDRAM_BASE + 16 * 1024 + CONFIG_SYS_MALLOC_F_LEN - \
+	 GENERATED_GBL_DATA_SIZE)
 
 /* NAND flash */
 #ifdef CONFIG_CMD_NAND