The Syrian conflict is affected by the ISIL push in Iraq in two ways. The first is that the jihadists may divert large numbers of fighters from Syria to its Iraq push, which would open ISIL to more pressure in Syria. The second impact is the withdrawal of large numbers of Iraqi Shiite militants -- men that have been fighting alongside the Syrian army -- leaving to concentrate their efforts back home against ISIL. Such a withdrawal would be unpopular in the Syrian regime because it would take away an important source of manpower.
I'll add another problem for Iraq in this porous border where the conflict spans the Iraq-Syria border. Iraq has been subject to Sunni Arab terrorists flowing in from Syria whether the Alawite government funneled in jihadis to fight their Shia cousins running Iraq or whether Sunni terrorists dominate eastern Syria and go in on their own.
I still think working to overthrow the Assad regime is a step in the right direction of ending the tails Iraq loses and heads the jihadis win dilemma.