intel-gpu-tools: fix problem with redefinition of mmap64

intel-gpu-tools: fix problem with redefinition of mmap64

In android builds there is no reliable way to determine if mmap64 is defined
or not, and this sometimes leads to a compile error due to its re-defnition.
So this commit avoids its use altogether in intel-gpu-tools for Android builds,
unless the HAVE_MMAP64 macro is defined.

Signed-off-by: Tim Gore <tim.gore@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>