rs780: Implement `rs780_internal_gfx_disable` and add .disable pcie_ops

That code will be used to disable the internal GFX card and enable the
external PCIe card.

The following lines from function `rs780_internal_gfx_enable()` are
taken and reversed.

	/* Disable external GFX and enable internal GFX. */
	l_dword = pci_read_config32(nb_dev, 0x8c);
	l_dword &= ~(1<<0);
	l_dword |= 1<<1;
	pci_write_config32(nb_dev, 0x8c, l_dword);

It has been tested on the M4A785T-M with the following card inside the
PCIe 16x slot:

  02:00.0 VGA compatible controller: nVidia Corporation GT218 [GeForce 210] (rev a2)

Change-Id: I7bd412b987fde98c97464175e2c7a384a8f0fb84
Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@no-log.org>
Signed-off-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-on: http://review.coreboot.org/2065
Tested-by: build bot (Jenkins)

0 files changed, 0 insertions, 0 deletions