Seth Forshee reported that his system was reporting that the EFI framebuffer
stretched from 0x90010000-0xb0010000 despite the GPU's BAR only covering
0x90000000-0x9ffffff. It's safer to calculate this value from the pixel
stride and screen height (values we already depend on) rather than face
potential problems with resource allocation later on.
Signed-off-by: NMatthew Garrett <mjg@redhat.com>
Tested-by: NSeth Forshee <seth.forshee@canonical.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>