SDMA4.4 and SDMA5.2+ has increased it's available copy size to 2^30 bytes
represented by exponent as bits set in the COUNT field of the
linear copy.
Also note that the full 2^22 byte limit is available from SDMA4 onwards
as it has corrected the 0x3fffe0 HW limitation from SDMA3.
As copy limit has increase, this can change system performance
so provide env var HSA_ENABLE_SDMA_COPY_SIZE_OVERRIDE=0 to fall
back to the original 0x3fffe0 limit for debugging purposes.
Change-Id: I0fb6e5378f68e5b8a00ff559271691a943ee06ee
Jonathan Kim
81c64228e0