Up to this point there's basically been a Linux kernel build for each ARM target/platform, which has been one of several problems complicating the ARM Linux platform. Fortunately with this multi-platform work merged for Linux 3.7, a single build is now able to target multiple platforms, in a somewhat similar manner to an x86 kernel image.
Not all ARM platforms are initially supported this way for the Linux 3.7 kernel. In this next kernel, the platforms where you can now have a single kernel image include highbank, vexpress, mvebu, socfpga, and picoxcell.
As Olof Johansson explains in the Git commit, "This is a pretty significant branch. It's the introduction of the first multiplatform support on ARM, and with this (and the later branch) merged, it is now possible to build one kernel that contains support for highbank, vexpress, mvebu, socfpga, and picoxcell. More platforms will be convered over in the next few releases."