INT 16,5 - Keyboard Buffer Write (AT+)

	AH = 05
	CH = scan code
	CL = ASCII character


	on return:
	AL = 00 if success
	     01 if buffer full


	- available on AT and PS/2 machines with extended keyboard support
	- stores normal keystroke into keyboard buffer
	- will not store attribute keys like Shift, Alt, Ctrl, etc...