temp_metrics: use iotools wrmsr instead of wrmsr

Use the "iotools wrmsr" command instead of the wrmsr alias since iotools
ebuild no longer installs the symlinks by default.

BUG=chromium-os:39180
TEST=On a Pixel issue "sudo start temp_metrics" and check
/var/log/messages to ensure that no new messages such as "init:
temp_metrics main process ended, respawning" show up.
BRANCH=none

Change-Id: I46cd8770c7e6c1af1affe8e2100033a29b9a90bb
Signed-off-by: Sameer Nanda <snanda@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/44073
Reviewed-by: Luigi Semenzato <semenzato@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>

util/temp_metrics.conf

@@ -158,13 +158,13 @@ script
   set_duty_cycle() {
     duty_cycle=$1
     for i in 0 1 2 3; do
-      wrmsr $i 0x19a $duty_cycle
+      iotools wrmsr $i 0x19a $duty_cycle
     done
   }
 
   set_pkg_power_limit() {
     pwr_limit=$1
-    wrmsr 0 0x610 $pwr_limit
+    iotools wrmsr 0 0x610 $pwr_limit
   }
 
   log_message() {
@@ -193,7 +193,7 @@ script
   thermal_loop() {
     # Hack to reset turbo activation threshold since BIOS can change it
     # underneath us.
-    wrmsr 0 0x64c 0x12
+    iotools wrmsr 0 0x64c 0x12
 
     skin_temp=$1
     if [ $skin_temp -gt $TEMP_THRESHOLD_3 ]; then