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

The dtpm_descr variable in init_dtpm() is not used after commit
f751db8adaea ("powercap/drivers/dtpm: Disable DTPM at boot time"),
so drop it.

Fixes: f751db8adaea ("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>
diff --git a/drivers/powercap/dtpm.c b/drivers/powercap/dtpm.c
index fb35c58..2a5c182 100644
--- a/drivers/powercap/dtpm.c
+++ b/drivers/powercap/dtpm.c
@@ -463,8 +463,6 @@
 
 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");