eventpoll.h: add missing epoll event masks

[resend due to me forgetting to cc: linux-api the first time around I
posted these back on Feb 23]

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

For some reason these values are not in the uapi header file, so any
libc has to define it themselves.  To prevent them from needing to do
this, just have the kernel provide the correct values.
Reported-by: Elliott Hughes <enh@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/uapi/linux/eventpoll.h

@@ -26,6 +26,19 @@
 #define EPOLL_CTL_DEL 2
 #define EPOLL_CTL_MOD 3
 
+/* Epoll event masks */
+#define EPOLLIN		0x00000001
+#define EPOLLPRI	0x00000002
+#define EPOLLOUT	0x00000004
+#define EPOLLERR	0x00000008
+#define EPOLLHUP	0x00000010
+#define EPOLLRDNORM	0x00000040
+#define EPOLLRDBAND	0x00000080
+#define EPOLLWRNORM	0x00000100
+#define EPOLLWRBAND	0x00000200
+#define EPOLLMSG	0x00000400
+#define EPOLLRDHUP	0x00002000
+
 /* Set exclusive wakeup mode for the target file descriptor */
 #define EPOLLEXCLUSIVE (1U << 28)