tune-cortexr*: add support for all Arm Cortex-R processors

Add tune entries for all Arm Cortex-R processors currently supported in
GCC.  Also, add the simd feature, which can be used in ARMv7a and
ARMv8a, but currently isn't.

Signed-off-by: Jon Mason <jdmason@kudzu.us>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>