keyboard: Use BIOS Keyboard variable to set Numlock

The PC BIOS does provide a NUMLOCK flag containing the desired state
of this LED. This patch sets the current state according to the data
in the bios.

[ hpa: fixed __weak declaration without definition, changed "inline"
  to "static inline" ]

Signed-Off-By: Joshua Cov <joshuacov@googlemail.com>
Link: http://lkml.kernel.org/r/CAKL7Q7rvq87TNS1T_Km8fW_5OzS%2BSbYazLXKxW-6ztOxo3zorg@mail.gmail.com
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>