OMAP: omap_device: use read_persistent_clock() instead of getnstimeofday()

During suspend and resume, when omap_device deactivation and
activation is happening, the timekeeping subsystem has likely already
been suspended.  Thus getnstimeofday() will fail and trigger a WARN().

Use read_persistent_clock() instead of getnstimeofday() to avoid this.

Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
diff --git a/arch/arm/plat-omap/omap_device.c b/arch/arm/plat-omap/omap_device.c
index 54fe0a2..9a502af 100644
--- a/arch/arm/plat-omap/omap_device.c
+++ b/arch/arm/plat-omap/omap_device.c
@@ -134,12 +134,12 @@
 		    (od->dev_wakeup_lat <= od->_dev_wakeup_lat_limit))
 			break;
 
-		getnstimeofday(&a);
+		read_persistent_clock(&a);
 
 		/* XXX check return code */
 		odpl->activate_func(od);
 
-		getnstimeofday(&b);
+		read_persistent_clock(&b);
 
 		c = timespec_sub(b, a);
 		act_lat = timespec_to_ns(&c) * NSEC_PER_USEC;
@@ -190,12 +190,12 @@
 		     od->_dev_wakeup_lat_limit))
 			break;
 
-		getnstimeofday(&a);
+		read_persistent_clock(&a);
 
 		/* XXX check return code */
 		odpl->deactivate_func(od);
 
-		getnstimeofday(&b);
+		read_persistent_clock(&b);
 
 		c = timespec_sub(b, a);
 		deact_lat = timespec_to_ns(&c) * NSEC_PER_USEC;