nios2: convert do_reset to use dm cpu data

Convert do_reset to use dm cpu data.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/nios2/cpu/cpu.c b/arch/nios2/cpu/cpu.c
index d7ff290..0e71b43 100644
--- a/arch/nios2/cpu/cpu.c
+++ b/arch/nios2/cpu/cpu.c
@@ -25,7 +25,7 @@
 {
 	disable_interrupts();
 	/* indirect call to go beyond 256MB limitation of toolchain */
-	nios2_callr(CONFIG_SYS_RESET_ADDR);
+	nios2_callr(gd->arch.reset_addr);
 	return 0;
 }