app-emulation/virtualbox: Attempt to fix build on amd64 no_multilib

Seems like I accidentally dropped some ebuild code in 6.1.0_rc1 that
should not have been dropped.

Thanks-to: Zdravko Spoljar <zdravko.spoljar@styria-it.hr>
Bug: https://bugs.gentoo.org/702674
Package-Manager: Portage-2.3.81, Repoman-2.3.20
Signed-off-by: Lars Wendler <polynomial-c@gentoo.org>

app-emulation/virtualbox/virtualbox-6.1.0.ebuild

@@ -244,6 +244,9 @@ src_configure() {
 			--disable-opengl
 		)
 	fi
+	if use amd64 && ! has_multilib_profile ; then
+		myconf+=( --disable-vmmraw )
+	fi
 	# not an autoconf script
 	doecho ./configure ${myconf[@]}
 }