drm/radeon/kms: fix typos in disabled vbios code

6xx/7xx was hitting the wrong BUS_CNTL reg and bits.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/r600_reg.h b/drivers/gpu/drm/radeon/r600_reg.h
index d84612a..33cda01 100644
--- a/drivers/gpu/drm/radeon/r600_reg.h
+++ b/drivers/gpu/drm/radeon/r600_reg.h
@@ -86,6 +86,7 @@
 #define R600_HDP_NONSURFACE_BASE                                0x2c04
 
 #define R600_BUS_CNTL                                           0x5420
+#       define R600_BIOS_ROM_DIS                                (1 << 1)
 #define R600_CONFIG_CNTL                                        0x5424
 #define R600_CONFIG_MEMSIZE                                     0x5428
 #define R600_CONFIG_F0_BASE                                     0x542C