Same computation for square and multiply.
* mpi/mpi-pow.c (_gcry_mpi_powm): Compare msize for max_u_size. Move the assignment to base_u into the loop. Copy content refered by RP to BASE_U except the last of the loop.
(backport from master commit:
78130828e9a140a9de4dafadbc844dbb64cb709a)
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>