Add support for Logitech MX300 in PS2++ driver

Hello.

This little patch adds support for Logitech MX300 mices. It is to be applied against 2.6.x kernel series. Please, have a look at it.

Patch follows ===

diff -u a/drivers/input/mouse/logips2pp.c b/drivers/input/mouse/logips2pp.c
@@ -172,6 +172,10 @@

		{ 100,	PS2PP_KIND_MX,
				PS2PP_WHEEL | PS2PP_SIDE_BTN | PS2PP_TASK_BTN |
				PS2PP_EXTRA_BTN | PS2PP_NAV_BTN },	/* MX510 */

+
+ { 111, PS2PP_KIND_MX,
+ PS2PP_WHEEL | PS2PP_EXTRA_BTN | PS2PP_TASK_BTN }, /* MX300 */
+

		{ 112,	PS2PP_KIND_MX,

PS2PP_WHEEL | PS2PP_SIDE_BTN | PS2PP_TASK_BTN |
PS2PP_EXTRA_BTN | PS2PP_NAV_BTN }, /* MX500 */