Converted the FRAMEBUFFER_VESA_MODE to a choice.

Being a diligent soul, I changed the "enter a numeric value for the
mode you want" option to a choice of common modes.  New modes can be
added quite easily.

Change-Id: I8cf4572c2d36ced6549541ec173c0c02d8eaca4a
Signed-off-by: Steve Goodrich <steve.goodrich@se-eng.com>
Reviewed-on: http://review.coreboot.org/1036
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marcj303@gmail.com>
1 file changed