hw/i386/pc: Remove "rtc_state" link again

hw/i386/pc: Remove "rtc_state" link again

Commit 99e1c1137b6f "hw/i386/pc: Populate RTC attribute directly" made linking
the "rtc_state" property unnecessary and removed it. Commit 84e945aad2d0 "vl,
pc: turn -no-fd-bootchk into a machine property" accidently reintroduced the
link. Remove it again since it is not needed.

Fixes: 84e945aad2d0 "vl, pc: turn -no-fd-bootchk into a machine property"
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Message-Id: <20240303185332.1408-2-shentey@gmail.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>