DVB: cx24123: fix PLL divisor setup

The cx24109 datasheet says: "NOTE: if A=0, then N=N+1"

The current code is the result of a misinterpretation of the datasheet to
mean exactly the opposite of the requirement -- The actual value of N is 1
greater than the value written when A is 0, so 1 needs to be *subtracted*
from it to compensate.
Signed-off-by: Yeasah Pell <yeasah@schwide.net>
Signed-off-by: Steven Toth <stoth@hauppauge.com>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/media/dvb/frontends/cx24123.c

@@ -549,8 +549,8 @@ static int cx24123_pll_calculate(struct dvb_frontend* fe, struct dvb_frontend_pa
 	ndiv = ( ((p->frequency * vco_div * 10) / (2 * XTAL / 1000)) / 32) & 0x1ff;
 	adiv = ( ((p->frequency * vco_div * 10) / (2 * XTAL / 1000)) % 32) & 0x1f;
 
-	if (adiv == 0)
-		ndiv++;
+	if (adiv == 0 && ndiv > 0)
+		ndiv--;
 
 	/* control bits 11, refdiv 11, charge pump polarity 1, charge pump current, ndiv, adiv */
 	state->pllarg = (3 << 19) | (3 << 17) | (1 << 16) | (pump << 14) | (ndiv << 5) | adiv;