Update joy.c
Update joy.c

Changed joyAxisY[port] in static u16 readMouse(u16 port) as Y axis was wrong (input was correctly captured but direction reversed).
andwn/SGDK,andwn/SGDK,Stephane-D/SGDK,Stephane-D/SGDK,Stephane-D/SGDK,andwn/SGDK