intel_rapl: need linux/cpuhotplug.h for enum cpuhp_state

Fixes: 7ebf8eff ("intel_rapl: introduce struct rapl_if_private")
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

include/linux/intel_rapl.h

@@ -12,6 +12,7 @@
 
 #include <linux/types.h>
 #include <linux/powercap.h>
+#include <linux/cpuhotplug.h>
 
 enum rapl_domain_type {
 	RAPL_DOMAIN_PACKAGE,	/* entire package/socket */