kconfig: remove redundant NULL pointer check before free()

Passing NULL to free() is allowed and is a no-op.

Remove redundant NULL pointer checks.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/kconfig/confdata.c

@@ -432,7 +432,6 @@ int conf_read_simple(const char *name, int def)
 		case S_INT:
 		case S_HEX:
 		case S_STRING:
-			if (sym->def[def].val)
 			free(sym->def[def].val);
 			/* fall through */
 		default:

scripts/kconfig/util.c

@@ -42,7 +42,6 @@ struct gstr str_new(void)
 /* Free storage for growable string */
 void str_free(struct gstr *gs)
 {
-	if (gs->s)
 	free(gs->s);
 	gs->s = NULL;
 	gs->len = 0;