There is a chip support package for OMAP5 available directly from the product group that adds in the device support files including peripheral register definitions. You need to get the package from the product group as it is still NDA only.
As far as A15 in the project wizard, we will likely add that in for CCSv5.5 (it will default to Linaro gcc baremetal). It is not there today as the TI compiler doesn't do anything special for A15 (i.e. it supports generating code targeted for A8 which will run on A15 but hasn't added support beyond A8). Most customers run an OS like Linux or Android on the A15 thus the TI compiler is not relevant. Do you have customers who are running baremetal or BIOS?
John