Drivers: hv: vmbus: Always use HV_HYP_PAGE_SIZE for gpadl

Drivers: hv: vmbus: Always use HV_HYP_PAGE_SIZE for gpadl

Since the hypervisor always uses 4K as its page size, the size of PFNs
used for gpadl should be HV_HYP_PAGE_SIZE rather than PAGE_SIZE, so
adjust this accordingly as the preparation for supporting 16K/64K page
size guests. No functional changes on x86, since PAGE_SIZE is always 4k
(equals to HV_HYP_PAGE_SIZE).

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20200916034817.30282-2-boqun.feng@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>