[bsp][sam7x] Fix compile error. Increase DATA section size in .ld file.

bsp/sam7x/sam7x_rom.ld

@@ -4,7 +4,7 @@ MEMORY
 {
     CODE (rx) : ORIGIN = 0x00100000, LENGTH = 0x00040000
     /* DATA (rw) : ORIGIN = 0x00200000, LENGTH = 0x00010000 */
-    DATA (rw) : ORIGIN = 0x00204000, LENGTH = 0x0000C000
+    DATA (rw) : ORIGIN = 0x00203000, LENGTH = 0x0000D000
 }
 ENTRY(_start)
 SECTIONS