[AArch64] Adjust the cost model for Exynos M1 and M2

Add the cost for the EXT instructions and explicitly add the cost for a few
instructions that were implied by the coarse model.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@308697 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed