Drivers: hv: vmbus: Remove the unused "tsc_page" from struct hv_context

This field is no longer used after the commit
63ed4e0c ("Drivers: hv: vmbus: Consolidate all Hyper-V specific clocksource code")
, because it's replaced by the global variable
"struct ms_hyperv_tsc_page *tsc_pg;" (now, the variable is in
drivers/clocksource/hyperv_timer.c).

Fixes: 63ed4e0c

 ("Drivers: hv: vmbus: Consolidate all Hyper-V specific clocksource code")
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>