powercap: RAPL: Fix struct declaration in header file

struct rapl_package is declared twice in intel_rapl.h, once at line 80
and once earlier.

Code inspection suggests that the first instance should be struct
rapl_domain rather than rapl_package, so change it.

Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

include/linux/intel_rapl.h

@@ -33,7 +33,7 @@ enum rapl_domain_reg_id {
 	RAPL_DOMAIN_REG_MAX,
 };
 
-struct rapl_package;
+struct rapl_domain;
 
 enum rapl_primitives {
 	ENERGY_COUNTER,