qemu_capabilities: replace code with function call

qemu_capabilities: replace code with function call

Since functions virQEMUCapsFillDomainFeatureSEVCaps() and
virQEMUCapsSEVInfoCopy() essentially do the same thing it does
not make sense to have the code duplicated. This patch replaces
the relevant code in the first function with the function call to
the second one.

Signed-off-by: Kristina Hanicova <khanicov@redhat.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Jonathon Jongsma <jjongsma@redhat.com>