board: phycore-imx93: env: Add option to disable bootenv.txt import

Add support for disabling external environment import (bootenv.txt) by
setting the ${no_bootenv} environment variable.

Signed-off-by: Primoz Fiser <primoz.fiser@norik.com>
diff --git a/board/phytec/phycore_imx93/phycore_imx93.env b/board/phytec/phycore_imx93/phycore_imx93.env
index 52c234a..d0694f2 100644
--- a/board/phytec/phycore_imx93/phycore_imx93.env
+++ b/board/phytec/phycore_imx93/phycore_imx93.env
@@ -20,8 +20,10 @@
 loadfdt=fatload mmc ${mmcdev}:${mmcpart} ${fdt_addr_r} ${fdtfile}
 mmcboot=
 	echo Booting from mmc ...;
-	if run mmc_load_bootenv; then
-		env import -t ${bootenv_addr_r} ${filesize};
+	if test ${no_bootenv} = 0; then
+		if run mmc_load_bootenv; then
+			env import -t ${bootenv_addr_r} ${filesize};
+		fi;
 	fi;
 	run mmcargs;
 	if run loadfdt; then
@@ -41,8 +43,10 @@
 	else
 		setenv get_cmd tftp;
 	fi;
-	if run net_load_bootenv; then
-		env import -t ${bootenv_addr_r} ${filesize};
+	if test ${no_bootenv} = 0; then
+		if run net_load_bootenv; then
+			env import -t ${bootenv_addr_r} ${filesize};
+		fi;
 	fi;
 	${get_cmd} ${loadaddr} ${image};
 	if ${get_cmd} ${fdt_addr_r} ${fdtfile}; then