soc/amd/picasso: Use read-modify-write for ACP_I2S_PIN_CONFIG

This change uses read-modify-write to update ACP_I2S_PIN_CONFIG instead of
a write operation since the other bits in the register are reserved.

Change-Id: Ic64e1907858ec293c5f759e627d19c00d748a30e
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43503
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/amd/picasso/acp.c b/src/soc/amd/picasso/acp.c
index b598e64..4efef18 100644
--- a/src/soc/amd/picasso/acp.c
+++ b/src/soc/amd/picasso/acp.c
@@ -41,7 +41,7 @@
 	}
 
 	bar = (uintptr_t)res->base;
-	write32((void *)(bar + ACP_I2S_PIN_CONFIG), cfg->acp_pin_cfg);
+	acp_update32(bar, ACP_I2S_PIN_CONFIG, PIN_CONFIG_MASK, cfg->acp_pin_cfg);
 
 	/* Enable ACP_PME_EN and ACP_I2S_WAKE_EN for I2S_WAKE event */
 	acp_update32(bar, ACP_I2S_WAKE_EN, WAKE_EN_MASK, !!cfg->acp_i2s_wake_enable);