MIPS: IP27: Migrate to new Platform file

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --cc arch/mips/Kbuild.platforms
Simple merge

diff --cc arch/mips/Makefile
Simple merge

diff --cc arch/mips/sgi-ip27/Makefile
Simple merge

diff --cc arch/mips/sgi-ip27/Platform
Simple merge