x11-drivers/xf86-video-vmware: Drop dependency on obsolete GCC

This port has not seen a code update for more than six years and
is stuck with an end-of-life version of GCC 11 on i386 which
should leave our tree soon.

Drop this dependency and make the port amd64-only.

PR: 283336
Approved by: maintainer timeout (freebsd-x11, 8 weeks)