configs/freescale_p1025twr_defconfig: new board

Replacing the p1010rdb, this board is based on the tower development
system still available by NXP. The board is setup to track upstream
Linux and has been bumped from 4.1 to 4.15 (compared to p1010).

The target does not build uboot and assumes the user still uses the NXP
suggested prebuilts in the SDK2.0 (last release for PowerPC). If a
uboot is required, the source for SDK2.0 can be found in the following
repo.
http://git.freescale.com/git/cgit.cgi/ppc/sdk/u-boot.git/tag/?id=fsl-sdk-v2.0-1703



Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>