ALSA: firewire-motu: Correct a typo in the clock proc string

Just fix a typo of "S/PDIF" in the clock name string.

Fixes: 4638ec6e ("ALSA: firewire-motu: add proc node to show current statuc of clock and packet formats")
Acked-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20191030100921.3826-1-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/motu/motu-proc.c

@@ -16,7 +16,7 @@ static const char *const clock_names[] = {
 	[SND_MOTU_CLOCK_SOURCE_SPDIF_ON_OPT] = "S/PDIF on optical interface",
 	[SND_MOTU_CLOCK_SOURCE_SPDIF_ON_OPT_A] = "S/PDIF on optical interface A",
 	[SND_MOTU_CLOCK_SOURCE_SPDIF_ON_OPT_B] = "S/PDIF on optical interface B",
-	[SND_MOTU_CLOCK_SOURCE_SPDIF_ON_COAX] = "S/PCIF on coaxial interface",
+	[SND_MOTU_CLOCK_SOURCE_SPDIF_ON_COAX] = "S/PDIF on coaxial interface",
 	[SND_MOTU_CLOCK_SOURCE_AESEBU_ON_XLR] = "AESEBU on XLR interface",
 	[SND_MOTU_CLOCK_SOURCE_WORD_ON_BNC] = "Word clock on BNC interface",
 	[SND_MOTU_CLOCK_SOURCE_SPH] = "Source packet header",