[media] drxk: Make the QAM demodulator command parameters configurable

Currently there are two different implementations (in the firmware) for
the QAM demodulator command: one takes 4 and the other takes 2
parameters. The driver shows an error in dmesg When using the
4-parameter command with firmware that implements the 2-parameter
command. Unfortunately this happens every time when chaning the
frequency (on DVB-C).

This patch simply makes configurable, how many command parameters will
be used. All existing drxk_config instances using the "drxk_a3.mc" were
updated because this firmware is the only loadable firmware where the
QAM demodulator command takes 4 parameters. Some firmwares in the ROM
might also use it. The drxk instances in the em28xx-dvb driver were also
updated to silence the warnings.

If no qam_demod_parameter_count is given in the drxk_config struct, then
the correct number of parameters will be auto-detected.

[mchehab@redhat.com: Fix a small CodingStyle issue at one comment]
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/dvb/frontends/drxk.h b/drivers/media/dvb/frontends/drxk.h
index 9d64e4f..d615d7d 100644
--- a/drivers/media/dvb/frontends/drxk.h
+++ b/drivers/media/dvb/frontends/drxk.h
@@ -20,6 +20,14 @@
  *			means that 1=DVBC, 0 = DVBT. Zero means the opposite.
  * @mpeg_out_clk_strength: DRXK Mpeg output clock drive strength.
  * @microcode_name:	Name of the firmware file with the microcode
+ * @qam_demod_parameter_count:	The number of parameters used for the command
+ *				to set the demodulator parameters. All
+ *				firmwares are using the 2-parameter commmand.
+ *				An exception is the "drxk_a3.mc" firmware,
+ *				which uses the 4-parameter command.
+ *				A value of 0 (default) or lower indicates that
+ *				the correct number of parameters will be
+ *				automatically detected.
  *
  * On the *_gpio vars, bit 0 is UIO-1, bit 1 is UIO-2 and bit 2 is
  * UIO-3.
@@ -38,7 +46,8 @@
 	u8	mpeg_out_clk_strength;
 	int	chunk_size;
 
-	const char *microcode_name;
+	const char	*microcode_name;
+	int		 qam_demod_parameter_count;
 };
 
 #if defined(CONFIG_DVB_DRXK) || (defined(CONFIG_DVB_DRXK_MODULE) \