media: dvb-frontends/stv0910: fix mask for scramblingcode setup

The scrambling code has 4 bits. Fix the mask accordingly.
Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/dvb-frontends/stv0910.c

@@ -1021,7 +1021,7 @@ static int start(struct stv *state, struct dtv_frontend_properties *p)
 		write_reg(state, RSTV0910_P2_PLROOT1 + state->regoff,
 			  (scrambling_code >> 8) & 0xff);
 		write_reg(state, RSTV0910_P2_PLROOT2 + state->regoff,
-			  (scrambling_code >> 16) & 0x07);
+			  (scrambling_code >> 16) & 0x0f);
 		state->cur_scrambling_code = scrambling_code;
 	}