It seems like Intel is hedging its bets.
It is essentially the best in the processor process treadmill, but this means exorbitant costs and greater risk.
If it scaled all its fabs in rapid succession (it usually doesn't do this, but 22nm sounds like a significant amount of expansion), its capacity would double every two years, and its R&D and other costs would more than double in the same time period.
At the same time mature markets are not growing anywhere near that rate, and developing markets may not be growing at that rate or may be favoring cheaper, smaller, products or Intel's continued growth may be less than certain in the long run due to regulation or governmental interference.
As others have noted, Intel could be testing the waters for giving a small amount of its capacity to third parties, or it could be interested in testing potential acquisitions that could then become components in its primary product lines, allowing them charge more for the product because it assimilates more of the independent parts of a full device.