Revert "Specify -mcpu=krait for clang"

This reverts commit 64d8bca539205e5fb40d7ebf7eb509585466ddd8.
Revert "Add Back Options to Select.mk"

This reverts commit 7f111183cde91211c3fdcdf0e8c7f0a0635c4e2d.
Try Allowing loop unrolling on thumb

Signed-off-by: Chet Kener <Cl3Kener@gmail.com>