[media] drx-j: Remove a bunch of unused but assigned vars

None of those vars are used on those functions. Just remove them.

After this patch, there's just one of such warnings:

	drivers/media/dvb-frontends/drx39xyj/drxj.c: In function 'ctrl_get_qam_sig_quality':
	drivers/media/dvb-frontends/drx39xyj/drxj.c:7872:6: warning: variable 'ber_cnt' set but not used [-Wunused-but-set-variable]
	  u32 ber_cnt = 0; /* BER count */

We'll keep it, as BER count will be useful when converting the
frontend to report statistics via DVBv5 API
Acked-by: Devin Heitmueller <dheitmueller@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>