imx: move imx8 sci header file to include/firmware/imx

Move imx8 sci header file to include/firmware/imx, then we could
use build macro to reuse some i.MX8 drivers for i.MX9, such as
drivers/cpu/imx8_cpu.c.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Stefano Babic <sbabic@denx.de>
diff --git a/arch/arm/mach-imx/imx8/misc.c b/arch/arm/mach-imx/imx8/misc.c
index de19955..0ce3036 100644
--- a/arch/arm/mach-imx/imx8/misc.c
+++ b/arch/arm/mach-imx/imx8/misc.c
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0+
 #include <common.h>
 #include <log.h>
-#include <asm/arch/sci/sci.h>
+#include <firmware/imx/sci/sci.h>
 #include <asm/mach-imx/sys_proto.h>
 #include <imx_sip.h>
 #include <linux/arm-smccc.h>