The calls to atmi_memcpy presently determine the direction of copy (host to
device or device to host) by storing pointers in a map during malloc and
looking up the pointers during memcpy. As each call site already knows the
direction, this stash+lookup can be eliminated.
This NFC will be followed by a functional one that deletes those map lookups.
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D89776
Change-Id: I1d9089bc1e56b3a9a30e334735fa07dee1f84990
aa616efbb3