staging: unisys: visorbus: move unisys_vmcall into visorchipset

The only one using unisys_vmcall was visorchipset.c, it can be moved into
the visorchipset file directly instead of being in a header file.

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