kconfig: remove P_ENV property type

This property is not set by anyone since commit 104daea1 ("kconfig:
reference environment variables directly and remove 'option env='").
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: NSam Ravnborg <sam@ravnborg.org>

scripts/kconfig/expr.h

@@ -185,7 +185,6 @@ enum prop_type {
 	P_SELECT,   /* select BAR */
 	P_IMPLY,    /* imply BAR */
 	P_RANGE,    /* range 7..100 (for a symbol) */
-	P_ENV,      /* value from environment variable */
 	P_SYMBOL,   /* where a symbol is defined */
 };
 

scripts/kconfig/qconf.cc

@@ -1149,7 +1149,6 @@ QString ConfigInfoView::debug_info(struct symbol *sym)
 		case P_DEFAULT:
 		case P_SELECT:
 		case P_RANGE:
-		case P_ENV:
 			debug += prop_get_type_name(prop->type);
 			debug += ": ";
 			expr_print(prop->expr, expr_print_help, &debug, E_NONE);

scripts/kconfig/symbol.c

@@ -1289,8 +1289,6 @@ const char *prop_get_type_name(enum prop_type type)
 	switch (type) {
 	case P_PROMPT:
 		return "prompt";
-	case P_ENV:
-		return "env";
 	case P_COMMENT:
 		return "comment";
 	case P_MENU: