Add missing includes to fix the following warnings:
xf86DGA.c: In function 'DGAProcessKeyboardEvent':
xf86DGA.c:1050: warning: implicit declaration of function 'UpdateDeviceState'
xf86DGA.c:1050: warning: nested extern declaration of 'UpdateDeviceState'
xf86Xinput.c: In function 'xf86ActivateDevice':
xf86Xinput.c:303: warning: implicit declaration of function 'AssignTypeAndName'
xf86Xinput.c:303: warning: nested extern declaration of 'AssignTypeAndName'
xf86Xinput.c:311: warning: implicit declaration of function 'DeviceIsPointerType'
xf86Xinput.c:311: warning: nested extern declaration of 'DeviceIsPointerType'
xf86Xinput.c:324: warning: implicit declaration of function 'XkbSetExtension'
xf86Xinput.c:324: warning: nested extern declaration of 'XkbSetExtension'
aee514cfb5