x86/svm: Introduce svm_emul_swint_injection()

x86/svm: Introduce svm_emul_swint_injection()

Software events require emulation in some cases on AMD hardware.  Introduce
svm_emul_swint_injection() to perform this emulation if necessary in
svm_inject_event(), which will cope with any sources of event, rather than
just those coming from x86_emulate().

This logic mirrors inject_swint() in the x86 instruction emulator.

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