imx: imx8mp_evk: Switch to BOOTSTD

Move env to imx8mp_evk.env.
Switch to support BOOTSTD with a bsp bootcmd as fallback.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/arch/arm/mach-imx/imx8m/Kconfig b/arch/arm/mach-imx/imx8m/Kconfig
index b254a50..0cf3c1b 100644
--- a/arch/arm/mach-imx/imx8m/Kconfig
+++ b/arch/arm/mach-imx/imx8m/Kconfig
@@ -227,6 +227,8 @@
 	select ARCH_MISC_INIT
 	select SPL_CRYPTO if SPL
 	imply OF_UPSTREAM
+	imply BOOTSTD_FULL
+	imply BOOTSTD_BOOTCOMMAND
 
 config TARGET_IMX8MP_NAVQP
 	bool "Emcraft Systems i.MX8M Plus NavQ+ board"