cmd: env: add env select command

Add the new command 'env select' to force the persistent storage
of environment, saved in gd->env_load_prio.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/cmd/nvedit.c b/cmd/nvedit.c
index f730e2e..d188c6a 100644
--- a/cmd/nvedit.c
+++ b/cmd/nvedit.c
@@ -802,6 +802,15 @@
 	return env_reload() ? 1 : 0;
 }
 #endif
+
+#if defined(CONFIG_CMD_NVEDIT_SELECT)
+static int do_env_select(struct cmd_tbl *cmdtp, int flag, int argc,
+			 char *const argv[])
+{
+	return env_select(argv[1]) ? 1 : 0;
+}
+#endif
+
 #endif /* CONFIG_SPL_BUILD */
 
 int env_match(uchar *s1, int i2)
@@ -1368,6 +1377,9 @@
 	U_BOOT_CMD_MKENT(erase, 1, 0, do_env_erase, "", ""),
 #endif
 #endif
+#if defined(CONFIG_CMD_NVEDIT_SELECT)
+	U_BOOT_CMD_MKENT(select, 2, 0, do_env_select, "", ""),
+#endif
 	U_BOOT_CMD_MKENT(set, CONFIG_SYS_MAXARGS, 0, do_env_set, "", ""),
 #if defined(CONFIG_CMD_ENV_EXISTS)
 	U_BOOT_CMD_MKENT(exists, 2, 0, do_env_exists, "", ""),
@@ -1456,6 +1468,9 @@
 #if defined(CONFIG_CMD_NVEDIT_LOAD)
 	"env load - load environment\n"
 #endif
+#if defined(CONFIG_CMD_NVEDIT_SELECT)
+	"env select [target] - select environment target\n"
+#endif
 #if defined(CONFIG_CMD_NVEDIT_EFI)
 	"env set -e [-nv][-bs][-rt][-at][-a][-i addr,size][-v] name [arg ...]\n"
 	"    - set UEFI variable; unset if '-i' or 'arg' not specified\n"