imx: Update FSL_MFGPROT config for iMX8M

Update the Kconfig and Makefile to allow build for iMX8M and
restrict the build only in u-boot.

Signed-off-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Gaurav Jain <gaurav.jain@nxp.com>
diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
index 9aa1d84..ad0fb36 100644
--- a/arch/arm/mach-imx/Kconfig
+++ b/arch/arm/mach-imx/Kconfig
@@ -137,7 +137,7 @@
 
 config FSL_MFGPROT
 	bool "Support the 'mfgprot' command"
-	depends on IMX_HAB && ARCH_MX7
+	depends on IMX_HAB && (ARCH_MX7 || ARCH_IMX8M)
 	help
 	  This option enables the manufacturing protection command
 	  which can be used has a protection feature for Manufacturing