configure: remove reference to removed option

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

configure

@@ -1035,7 +1035,6 @@ Advanced options (experts only):
   --with-git-submodules=ignore   do not update or check git submodules (default if no .git dir)
   --static                 enable static build [$static]
   --bindir=PATH            install binaries in PATH
-  --efi-aarch64=PATH       PATH of efi file to use for aarch64 VMs.
   --with-suffix=SUFFIX     suffix for QEMU data inside datadir/libdir/sysconfdir/docdir [$qemu_suffix]
   --without-default-features default all --enable-* options to "disabled"
   --without-default-devices  do not include any device that is not needed to