staging: unisys: visorbus: remove unused functions in visorchipset

Removed unused functions issue_vmcall_update_physical_time() and
issue_vmcall_query_guest_virtual_time_offset() from visorchipset.c

Signed-off-by: Sameer Wadgaonkar <sameer.wadgaonkar@unisys.com>
Signed-off-by: David Kershner <david.kershner@unisys.com>
Reviewed-by: Tim Sell <timothy.sell@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>