ANDROID: trusty: Make Trusty driver page size agnostic

The FW interface expects number of 4K pages when memory is shared.
However the driver and the FW share memory in contigous memory areas,
so converting the number of kernel size pages to Trusty FW size pages
makes the Trusty kernel driver page size agnostic.

Bug: 294914413
Bug: 265047549
Bug: 267220208
Change-Id: Ie0b88c9cb30a0a16ea67f8046c7d0def2886c93f
Signed-off-by: Gabor Kertesz <gabor.kertesz@arm.com>
[ Kalesh Singh - Round up vds buffer allocation size to page boundary ]
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>