[Intel-gfx] [PATCH 0/3 V2] enabling sdvo-lvds if edid is not available.

[Ma Ling]

Currently Our SDVO support basic SDVO-LVDS resolution, it is enough for
most users. Because the mode lines are from EDID, monitor could show
nothing if driver fail to fetch EDID and default modes can't work for
SDVO LVDS. In order to avoid this case, the patch intends to fetch mode
lines from VBT and reserve them when driver initialize, then transmit
them to Xorg if driver can not fetch EDID in sdvo get modes function.
Based on crt present option in VBT, the patch also set corresponding
flag for VGA output.

It fixed bug #20241

[PATCH 1/3]Fetch mode lines from VBT, then reserve them
[PATCH 2/3]Set crt_present flag according to option in Block #1 of VBT 
[PATCH 3/3]Provide mode lines from VBT to xorg