nios2: remove CONFIG_SYS_INIT_SP macro

Remove CONFIG_SYS_INIT_SP macro, as the initial stack is set to
below the u-boot code.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Reviewed-by: Marek Vasut <marex@denx.de>
Reviewed-by: Chin Liang See <clsee@altera.com>

arch/nios2/cpu/start.S

@@ -81,6 +81,7 @@ _cur:	movhi	r5, %hi(_cur - _start)
 	mov	r8, r4
 	movhi	r5, %hi(_start)
 	ori	r5, r5, %lo(_start)	/* r5 <- linked _start */
+	mov	sp, r5		/* initial stack below u-boot code */
 	beq	r4, r5, 3f
 
 	movhi	r6, %hi(CONFIG_SYS_MONITOR_LEN)
@@ -100,8 +101,6 @@ _cur:	movhi	r5, %hi(_cur - _start)
 _reloc:
 
 	/* STACK INIT -- zero top two words for call back chain. */
-	movhi	sp, %hi(CONFIG_SYS_INIT_SP)
-	ori	sp, sp, %lo(CONFIG_SYS_INIT_SP)
 	addi	sp, sp, -8
 	stw	r0, 0(sp)
 	stw	r0, 4(sp)

include/configs/nios2-generic.h

@@ -84,7 +84,6 @@
 					 CONFIG_SYS_SDRAM_SIZE - \
 					 CONFIG_SYS_MONITOR_LEN)
 #define CONFIG_SYS_MALLOC_LEN		(CONFIG_ENV_SIZE + 0x20000)
-#define CONFIG_SYS_INIT_SP		CONFIG_SYS_MALLOC_BASE
 
 /*
  * MISC