fw_env.h: added a few missing defines

The README file lists 4 defined that were not actually present in the .h
file but that were needed to get things working with settings compiled in.
They are
Added these to the .h file
(the values above are the ones from the README file)

Signed-off-by: Frans Meulenbroeks <fransmeulenbroeks@gmail.com>

tools/env/fw_env.h

@@ -34,8 +34,12 @@
 #define DEVICE2_NAME      "/dev/mtd2"
 #define DEVICE1_OFFSET    0x0000
 #define ENV1_SIZE         0x4000
+#define DEVICE1_ESIZE     0x4000
+#define DEVICE1_ENVSECTORS     2
 #define DEVICE2_OFFSET    0x0000
 #define ENV2_SIZE         0x4000
+#define DEVICE2_ESIZE     0x4000
+#define DEVICE2_ENVSECTORS     2
 
 #define CONFIG_BAUDRATE		115200
 #define CONFIG_BOOTDELAY	5	/* autoboot after 5 seconds	*/