[bsp][sam9260] Remove unused macro define for assemble start files.

bsp/at91sam9260/platform/rt_low_level_gcc.inc

@@ -29,5 +29,3 @@
 .equ IRQ_STK_SIZE,    4096
 .equ FIQ_STK_SIZE,    4096
 .equ SYS_STK_SIZE,    2048
-/* vector table start should be 0x00000000 or 0xFFFF0000 */
-.equ VECTOR_TABLE_START,    0x00000000

bsp/at91sam9260/platform/rt_low_level_iar.inc

@@ -29,5 +29,3 @@
 #define IRQ_STK_SIZE 1024
 #define FIQ_STK_SIZE 1024
 #define SYS_STK_SIZE 512
-/* vector table start should be 0x00000000 or 0xFFFF0000 */
-#define VECTOR_TABLE_START    0x00000000

bsp/at91sam9260/platform/rt_low_level_keil.inc

@@ -29,6 +29,4 @@ ABT_STK_SIZE EQU 512
 IRQ_STK_SIZE EQU 1024
 FIQ_STK_SIZE EQU 1024
 SYS_STK_SIZE EQU 512
-;/* vector table start should be 0x00000000 or 0xFFFF0000 */
-VECTOR_TABLE_START EQU  0x00000000
     END