x86/resctrl: Fix a silly -Wunused-but-set-variable warning

clang correctly complains

  arch/x86/kernel/cpu/resctrl/rdtgroup.c:1456:6: warning: variable \
     'h' set but not used [-Wunused-but-set-variable]
          u32 h;
              ^

but it can't know whether this use is innocuous or really a problem.
There's a reason why those warning switches are behind a W=1 and not
enabled by default - yes, one needs to do:

  make W=1 CC=clang HOSTCC=clang arch/x86/kernel/cpu/resctrl/

with clang 14 in order to trigger it.

I would normally not take a silly fix like that but this one is simple
and doesn't make the code uglier so...
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/202301242015.kbzkVteJ-lkp@intel.com

arch/x86/kernel/cpu/resctrl/rdtgroup.c

@@ -1453,17 +1453,17 @@ static void mon_event_config_read(void *info)
 {
 	struct mon_config_info *mon_info = info;
 	unsigned int index;
-	u32 h;
+	u64 msrval;
 
 	index = mon_event_config_index_get(mon_info->evtid);
 	if (index == INVALID_CONFIG_INDEX) {
 		pr_warn_once("Invalid event id %d\n", mon_info->evtid);
 		return;
 	}
-	rdmsr(MSR_IA32_EVT_CFG_BASE + index, mon_info->mon_config, h);
+	rdmsrl(MSR_IA32_EVT_CFG_BASE + index, msrval);
 
 	/* Report only the valid event configuration bits */
-	mon_info->mon_config &= MAX_EVT_CONFIG_BITS;
+	mon_info->mon_config = msrval & MAX_EVT_CONFIG_BITS;
 }
 
 static void mondata_config_read(struct rdt_domain *d, struct mon_config_info *mon_info)