[gpm] [patch] fix gpm synps2 4-way-button support

[Mike Frysinger]

Pavel Semerad submitted this patch to Gentoo since we cant directly test the 
change w/out the aforementioned hardware :)

URL for more info:
http://bugs.gentoo.org/show_bug.cgi?id=36790

URL for patch:
http://bugs.gentoo.org/attachment.cgi?id=23004

Quick summary:
I found there are errors in synaptics.c source file. One is overwriting memory
(other variables) and second is assign of synaptics internal numbers to
state->buttons (struct Gpm_Event).

This patch solves it. Array boundaries must be set to 8, because of for
cycle in tp_process_repeating_actions(). And assign of last_4_way_buttons
cannot be done to state->buttons. I have commented it out (and it seems to
work), but may be this is not the correct solution.
-mike