VCCO of the bank should be set to 1.8 for LVDS, or 2.5V for LVDS_25, if you want to use the internal termination resistor (enabled with DIFF_TERM = TRUE, I recommended that you use it for best results).
If you use an external termination resistor you can use a VCCO that is different than the two mentioned but there are various criteria that must be met.
Read UG471 - Rules for Combining I/O Standards in the Same Bank, starting at pg 97 if you plan on using a different VCCO voltage.