Input: add eGalaxTouch serial touchscreen driver

There are two EETI touchscreen drivers in the kernel (eeti_ts and
egalax_ts) but both are for I2C-connected panels. This is for a different,
serial and not multi-touch touchscreen panel. The protocol documentation is
at http://www.eeti.com.tw/pdf/Software%20Programming%20Guide_v2.0.pdf

Signed-off-by: Böszörményi Zoltán <zboszor@pr.hu>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
diff --git a/include/uapi/linux/serio.h b/include/uapi/linux/serio.h
index becdd78..c2ea169 100644
--- a/include/uapi/linux/serio.h
+++ b/include/uapi/linux/serio.h
@@ -77,5 +77,6 @@
 #define SERIO_PS2MULT	0x3c
 #define SERIO_TSC40	0x3d
 #define SERIO_WACOM_IV	0x3e
+#define SERIO_EGALAX	0x3f
 
 #endif /* _UAPI_SERIO_H */