gpu-compute: Explicitly use little endian packet accessors.

The gpu ISA doesn't have a well defined endianness, but it really
should. It seems that the GPU is only used with x86, and in that
context it would be little endian.

Change-Id: I1620906564a77f44553fbf6d788866e017b6054b
Reviewed-on: https://gem5-review.googlesource.com/c/13463
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.com>
1 file changed