kconfig: remove useless NULL pointer check in conf_write_dep()

conf_write_dep() has just one caller:

    conf_write_dep("include/config/auto.conf.cmd");

"name" always points to a valid string.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

scripts/kconfig/confdata.c

@@ -964,8 +964,6 @@ static int conf_write_dep(const char *name)
 	struct file *file;
 	FILE *out;
 
-	if (!name)
-		name = ".kconfig.d";
 	out = fopen("..config.tmp", "w");
 	if (!out)
 		return 1;