MIPS: Sort MIPS Kconfig Alphabetically.

Sort the entries in config MIPS alphabetically so as to make entries
easier to find.

Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/16068/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>