x86/svm: Clean up intinfo_t variables

x86/svm: Clean up intinfo_t variables

The type name is poor because the type is also used for the IDT vectoring
field, not just for the event injection field.  Rename it to intinfo_t which
is how the APM refers to the data.

Rearrange the union to drop the .fields infix, and rename bytes to the more
common raw.  Also take the opportunity to rename the fields in the VMCB to
increase legibility.

While adjusting all call sites, fix up style issues and make use of structure
assignments where applicable.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>