powercap: DTPM: Drop unused local variable from init_dtpm()

The dtpm_descr variable in init_dtpm() is not used after commit
f751db8ada ("powercap/drivers/dtpm: Disable DTPM at boot time"),
so drop it.

Fixes: f751db8ada ("powercap/drivers/dtpm: Disable DTPM at boot time")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/powercap/dtpm.c

@@ -463,8 +463,6 @@ int dtpm_register(const char *name, struct dtpm *dtpm, struct dtpm *parent)
 
 static int __init init_dtpm(void)
 {
-	struct dtpm_descr *dtpm_descr;
-
 	pct = powercap_register_control_type(NULL, "dtpm", NULL);
 	if (IS_ERR(pct)) {
 		pr_err("Failed to register control type\n");