x86/hvm/ioreq: MMIO range checking completely ignores direction flag

x86/hvm/ioreq: MMIO range checking completely ignores direction flag

hvm_select_ioreq_server() is used to route an ioreq to the appropriate
ioreq server. For MMIO this is done by comparing the range of the ioreq
to the ranges registered by the device models of each ioreq server.
Unfortunately the calculation of the range if the ioreq completely ignores
the direction flag and thus may calculate the wrong range for comparison.
Thus the ioreq may either be routed to the wrong server or erroneously
terminated by null_ops.

NOTE: The patch also fixes whitespace in the switch statement to make it
      style compliant.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>