kconfig: do not include both curses.h and ncurses.h for nconfig

nconf.h includes <curses.h> and "ncurses.h", but it does not need to
include both.  Generally, it should fall back to curses.h only when
ncurses.h is not found.  But, looks like it has never happened;
these includes have been here for many years since commit 692d97c3
("kconfig: new configuration interface (nconfig)"), and nobody has
complained about hard-coding of ncurses.h .  Let's simply drop the
curses.h inclusion.

I replaced "ncurses.h" with <ncurses.h> since it is not a local file.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

scripts/kconfig/nconf.h

@@ -15,7 +15,7 @@
 #include <string.h>
 #include <unistd.h>
 #include <locale.h>
-#include <curses.h>
+#include <ncurses.h>
 #include <menu.h>
 #include <panel.h>
 #include <form.h>
@@ -24,8 +24,6 @@
 #include <time.h>
 #include <sys/time.h>
 
-#include "ncurses.h"
-
 #define max(a, b) ({\
 		typeof(a) _a = a;\
 		typeof(b) _b = b;\