Revert "rockchip: Allow booting from SPI"

This reverts commit 3523c07867.

Booting from SPI was already allowed before this commit was first
introduced. A few lines further down the exact same code already existed
and still does.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>

arch/arm/mach-rockchip/spl-boot-order.c

@@ -65,9 +65,6 @@ static int spl_node_to_boot_device(int node)
 		default:
 			return -ENOSYS;
 		}
-	} else if (!uclass_get_device_by_of_offset(UCLASS_SPI_FLASH, node,
-		&parent)) {
-		return BOOT_DEVICE_SPI;
 	}
 
 	/*