ASoC: wcd9310: make HPH status registers as volatile

HPH status registers are read-only registers that can be changed by
hardware.  Make those as volatile so not to cache it.

Change-Id: Iaf894ec2776ad757de147a55695ac04b1ecf4ad5
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
diff --git a/sound/soc/codecs/wcd9310.c b/sound/soc/codecs/wcd9310.c
index cad9907..5d77afd 100644
--- a/sound/soc/codecs/wcd9310.c
+++ b/sound/soc/codecs/wcd9310.c
@@ -3546,6 +3546,10 @@
 	if (tabla_is_digital_gain_register(reg))
 		return 1;
 
+	/* HPH status registers */
+	if (reg == TABLA_A_RX_HPH_L_STATUS || reg == TABLA_A_RX_HPH_R_STATUS)
+		return 1;
+
 	return 0;
 }