imx9: container.cfg: Guard tee.bin inclusion

Guard the inclusion of tee.bin with the CONFIG_OPTEE symbol to fix the
following build warning:

  CHECK    u-boot-container.cfgout
WARNING './tee.bin' not found, resulting binary may be not-functional
  BINMAN  .binman_stamp
  OFCHK   .config

Signed-off-by: Fabio Estevam <festevam@denx.de>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
diff --git a/arch/arm/mach-imx/imx9/container.cfg b/arch/arm/mach-imx/imx9/container.cfg
index 91a9731..a018c36 100644
--- a/arch/arm/mach-imx/imx9/container.cfg
+++ b/arch/arm/mach-imx/imx9/container.cfg
@@ -12,4 +12,6 @@
 IMAGE A55 bl31.bin 0x204E0000
 #endif
 IMAGE A55 u-boot.bin CONFIG_TEXT_BASE
+#ifdef CONFIG_OPTEE
 IMAGE A55 tee.bin 0x96000000
+#endif