[Matrix] Adjust matrix pointer type for inline asm arguments.

Matrix types in memory are represented as arrays, but accessed through
vector pointers, with the alignment specified on the access operation.

For inline assembly, update pointer arguments to use vector pointers.
Otherwise there will be a mis-match if the matrix is also an
input-argument which is represented as vector.

Reviewed By: nickdesaulniers

Differential Revision: https://reviews.llvm.org/D91631