86xx: remove the redundant r2 global data pointer save

The commit 67256678f00c09b0a7f19e862e5c1847553d31bc add
the another global data pointer save, but in fact the
global data pointer will be initialized in the board_init_r,
so remove it such as the 85xx/83xx family.

Signed-off-by: Dave Liu <daveliu@freescale.com>
Acked-by: Kumar Gala <kumar.gala@freescale.com>

cpu/mpc86xx/start.S

@@ -620,7 +620,6 @@ relocate_code:
 
 	mr	r1,  r3		/* Set new stack pointer		*/
 	mr	r9,  r4		/* Save copy of Global Data pointer	*/
-	mr	r2,  r9		/* Save for DECLARE_GLOBAL_DATA_PTR	*/
 	mr	r10, r5		/* Save copy of Destination Address	*/
 
 	mr	r3,  r5				/* Destination Address	*/