[coreboot] [patch] add missing code for rs780 lane reversal

[Bao, Zheng]

Before lane reversal,
De-asserts STRAP_BIF_all_valid for PCIE-GFX core.
After lane reversal,
Asserts STRAP_BIF_all_valid for PCIE-GFX core.

Signed-off-by: Zheng Bao

Index: src/southbridge/amd/rs780/rs780_gfx.c
===================================================================
--- src/southbridge/amd/rs780/rs780_gfx.c	(revision 6137)
+++ src/southbridge/amd/rs780/rs780_gfx.c	(working copy)
@@ -1302,8 +1302,10 @@
    	if(is_dev3_present()){
    		/* step 1, lane reversal (only need if CMOS
option is enabled) */
    		if (cfg->gfx_lane_reversal) {
+				set_nbmisc_enable_bits(nb_dev, 0x36, 1
<< 31, 1 << 31);
    			set_nbmisc_enable_bits(nb_dev, 0x33, 1
<< 2, 1 << 2);
    			set_nbmisc_enable_bits(nb_dev, 0x33, 1
<< 3, 1 << 3);
+				set_nbmisc_enable_bits(nb_dev, 0x36, 1
<< 31, 0 << 31);
    		}
    		printk(BIOS_DEBUG, "rs780_gfx_init step1.\n");
    		/* step 1.1, dual-slot gfx configuration (only
need if CMOS option is enabled) */
@@ -1317,10 +1319,11 @@

}else{
    		if (cfg->gfx_lane_reversal) {
+				set_nbmisc_enable_bits(nb_dev, 0x36, 1
<< 31, 1 << 31);
    			set_nbmisc_enable_bits(nb_dev, 0x33, 1
<< 2, 1 << 2);
+				set_nbmisc_enable_bits(nb_dev, 0x36, 1
<< 31, 0 << 31);
    		}
    		printk(BIOS_DEBUG, "rs780_gfx_init step1.\n");
-			printk(BIOS_DEBUG, "rs780_gfx_init step2.\n");

if((dev->path.pci.devfn >> 3) == 2)
    			single_port_configuration(nb_dev, dev);