video: adf: remove PAGE_SIZE from userspace-facing header

Systems may define PAGE_SIZE in userspace limits.h but don't have to.
PAGE_SIZE was picked as an arbitrary "reasonable" limit so just use 4096
instead.

Change-Id: I9555e39aba64a3a70f61eb6ded2a4129ab236ce0
Signed-off-by: Greg Hackmann <ghackmann@google.com>
Git-commit: b95f5c534f2ca5c2dfd341732afadce10b306ecd
Git-Repo: https://android.googlesource.com/kernel/common.git


Signed-off-by: Ian Maund <imaund@codeaurora.org>