dib0090: comment out the unused tables

Those tables are currently unused, so comment them out:

drivers/media/dvb-frontends/dib0090.c:852:18: warning: 'rf_ramp_pwm_sband' defined but not used [-Wunused-const-variable=]
 static const u16 rf_ramp_pwm_sband[] = {
                  ^~~~~~~~~~~~~~~~~
drivers/media/dvb-frontends/dib0090.c:800:18: warning: 'bb_ramp_pwm_boost' defined but not used [-Wunused-const-variable=]
 static const u16 bb_ramp_pwm_boost[] = {
                  ^~~~~~~~~~~~~~~~~

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>