Drivers: hv: util: Use hv_get_current_tick() to get current tick

BugLink: http://bugs.launchpad.net/bugs/1676635

As part of the effort to interact with Hyper-V in an instruction set
architecture independent way, use the new API to get the current
tick.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 305f7549)
Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Acked-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

drivers/hv/hv_util.c

@@ -27,6 +27,7 @@
 #include <linux/sysctl.h>
 #include <linux/reboot.h>
 #include <linux/hyperv.h>
+#include <asm/mshyperv.h>
 
 #include "hyperv_vmbus.h"
 
@@ -199,7 +200,7 @@ static void hv_set_host_time(struct work_struct *work)
 		 */
 		u64 current_tick;
 
-		rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
+		hv_get_current_tick(current_tick);
 		newtime += (current_tick - wrk->ref_time);
 	}
 	host_tns = (newtime - WLTIMEDELTA) * 100;