x86/HVM: remove identical relationship between ioreq type and rangeset type

x86/HVM: remove identical relationship between ioreq type and rangeset type

This patch uses HVMOP_IO_RANGE_XXX values rather than the raw ioreq
type to select the ioreq server, therefore the identical relationship
between ioreq type and rangeset type is no longer necessary.

Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Signed-off-by: Shuai Ruan <shuai.ruan@linux.intel.com>
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>