gpu: ion: Modify the system heap to try to allocate large/huge pages

On some systems there is a performance benefit to reducing tlb pressure
by minimizing the number of chunks in an allocation.

Change-Id: Ie6ff215a5f32a837bf3103f79a09748e38759f0e
Signed-off-by: Rebecca Schultz Zavin <rebecca@android.com>
Git-commit: 1fdd15d9b1e4531174a11f503b8989a1864e06bc
Git-repo: https://android.googlesource.com/kernel/common


[mitchelh@codeaurora.org: minor merge conflicts]
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>