ALSA: hdsp - Fix zero division

patch 2a3988f6 in mainline.

Fix zero-division bug in the calculation dds offset.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Cc: Maarten Bressers <mbressers@gmail.com>
Cc: gentoo kernel <kernel@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

sound/pci/rme9652/hdsp.c

@@ -3108,6 +3108,9 @@ static int hdsp_dds_offset(struct hdsp *hdsp)
 	unsigned int dds_value = hdsp->dds_value;
 	int system_sample_rate = hdsp->system_sample_rate;
 
+	if (!dds_value)
+		return 0;
+
 	n = DDS_NUMERATOR;
 	/*
 	 * dds_value = n / rate