mfd: intel-lpss: Use writeq() helper

There are already helper functions to do 64-bit I/O on 32-bit machines, thus we
don't need to reinvent the wheel. In our case we can't use readq() / writeq()
even on 64-bit kernel since there is a hardware limitation (OCP bus is a 32-bit
bus).

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
diff --git a/drivers/mfd/intel-lpss.c b/drivers/mfd/intel-lpss.c
index fdf4d5c..001a7d7 100644
--- a/drivers/mfd/intel-lpss.c
+++ b/drivers/mfd/intel-lpss.c
@@ -26,6 +26,8 @@
 #include <linux/pm_runtime.h>
 #include <linux/seq_file.h>
 
+#include <asm-generic/io-64-nonatomic-lo-hi.h>
+
 #include "intel-lpss.h"
 
 #define LPSS_DEV_OFFSET		0x000
@@ -52,8 +54,7 @@
 #define LPSS_PRIV_SSP_REG		0x20
 #define LPSS_PRIV_SSP_REG_DIS_DMA_FIN	BIT(0)
 
-#define LPSS_PRIV_REMAP_ADDR_LO		0x40
-#define LPSS_PRIV_REMAP_ADDR_HI		0x44
+#define LPSS_PRIV_REMAP_ADDR		0x40
 
 #define LPSS_PRIV_CAPS			0xfc
 #define LPSS_PRIV_CAPS_NO_IDMA		BIT(8)
@@ -250,12 +251,7 @@
 {
 	resource_size_t addr = lpss->info->mem->start;
 
-	writel(addr, lpss->priv + LPSS_PRIV_REMAP_ADDR_LO);
-#if BITS_PER_LONG > 32
-	writel(addr >> 32, lpss->priv + LPSS_PRIV_REMAP_ADDR_HI);
-#else
-	writel(0, lpss->priv + LPSS_PRIV_REMAP_ADDR_HI);
-#endif
+	lo_hi_writeq(addr, lpss->priv + LPSS_PRIV_REMAP_ADDR);
 }
 
 static void intel_lpss_deassert_reset(const struct intel_lpss *lpss)