arm: imx: move container Kconfig under mach-imx

Since i.MX8 and i.MX8ULP reuse common container, so move the Kconfig
public to both.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
index c089664..653463a 100644
--- a/arch/arm/mach-imx/Kconfig
+++ b/arch/arm/mach-imx/Kconfig
@@ -172,3 +172,16 @@
 	  the ROM code to configure the device at early boot stage, is located.
 	  This information is shared with the user via mkimage -l just so the
 	  image can be signed.
+
+config SPL_LOAD_IMX_CONTAINER
+	bool "Enable SPL loading U-Boot as a i.MX Container image"
+	depends on SPL
+	help
+	  This is to let SPL could load i.MX Container image
+
+config IMX_CONTAINER_CFG
+	string "i.MX Container config file"
+	depends on SPL
+	help
+	  This is to specific the cfg file for generating container
+	  image which will be loaded by SPL.
diff --git a/arch/arm/mach-imx/imx8/Kconfig b/arch/arm/mach-imx/imx8/Kconfig
index 71221d8..b43739e 100644
--- a/arch/arm/mach-imx/imx8/Kconfig
+++ b/arch/arm/mach-imx/imx8/Kconfig
@@ -31,19 +31,6 @@
 config SYS_SOC
 	default "imx8"
 
-config SPL_LOAD_IMX_CONTAINER
-	bool "Enable SPL loading U-Boot as a i.MX Container image"
-	depends on SPL
-	help
-	  This is to let SPL could load i.MX8 Container image
-
-config IMX_CONTAINER_CFG
-	string "i.MX Container config file"
-	depends on SPL
-	help
-	  This is to specific the cfg file for generating container
-	  image which will be loaded by SPL.
-
 config BOOTAUX_RESERVED_MEM_BASE
 	hex "i.MX auxiliary core dram memory base"
 	default 0