[media] stb0899: sign of CRL_FREQ doesn't depend on inversion

Contrary to CFR (derotator frequency), which changes signedness
depending on inversion, CRL_FREQ does not.

Signed-off-by: Reinhard Nißl <rnissl@gmx.de>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>